Dynamic Fixation Research Articles

A 3-Dimensional Printed Dynamic External Fixator for the Treatment of Proximal Interphalangeal Fracture-Dislocations: A Biomechanical Study

This study evaluated the efficacy of a 3-dimensional printed dynamic external fixator for treating proximal interphalangeal (PIP) fracture-dislocations. The null hypothesis was that there would be no difference in maintaining PIP joint reduction between a 3-dimensional printed dynamic external fixator (3DPDEF) and the pins and rubbers traction system (PRTS). Ten cadaveric fingers underwent an oblique osteotomy at the base of the middle phalanx, recreating an unstable dorsal PIP fracture-dislocation. The percentages of compromised articular surface and middle phalanx dorsal displacement were measured. Both fixators were randomly placed on each digit and underwent 1,400 flexion-extension cycles. Efficacy, determined by joint reduction and maintenance of dorsal translation correction, was assessed using fluoroscopy before and after the cycles. The mean compromised articular surface was 50.8%. After osteotomy, PIP joint subluxation occurred at 37.8° flexion. Dorsal translation after osteotomies was 2.8 mm. After applying the 3DPDEF and the PRTS, it was 0 mm and 0.1 mm, respectively. During the cycles, all the joints remained stable and reduced. Dorsal displacement after cycles was-0.1 mm for the 3DPDEF and 0 mm for the PRTS. The mean translation difference between both fixators was 0.1 and 0 mm before and after the cycles. The translation differences before and after the cycles were 0.1 mm for both dynamic fixators. The 3DPDEF is a suitable option for PIP fracture-dislocations, providing stability comparable to that of the PRTS while offering benefits, such as easy placement, controlled distraction, and clear visualization of the articular surface. This external fixator, characterized by its efficacy, low cost, and simplicity of application, broadens the options available to address PIP fracture-dislocations.

Differences in gait analysis and clinical outcome after dynamic fixation or screw fixation in acute syndesmosis tear: a prospective randomized pilot study.

Acute syndesmosis tears can be treated by static screw or dynamic fixation. Various studies have compared these techniques regarding postoperative outcome. However, to our knowledge, no study has used 3D-instrumented gait analysis (IGA). We hypothesized that a dynamic fixation would perform non-inferior to screw fixation in terms of biomechanical and clinical outcomes. Patients were prospectively randomized to both groups. All patients received the same follow-up rehabilitation and consultations (6 and 12 weeks; 6 and 12 months) postoperatively. Standardized questionnaires were used to objectify pain and ankle function. At 6 months follow-up, IGA was conducted additionally to objectify the biomechanical outcome. Twenty-five patients in the dynamic fixation (DF) group using TightRope® and twenty-five in the screw fixation group (SF) completed gait analysis. The DF group showed significantly higher mean values for maximum moment in the affected ankle joint (DF: 1.40 ± 0.21 Nm, SF: 1.23 ± 0.30 Nm; p = 0.023) and the unaffected ankle joint (DF: 1.52 ± 0.20 Nm, SF: 1.37 ± 0.27 Nm; p = 0.035). The difference between the affected and unaffected ankle joint was significantly higher in the SF group for active plantarflexion (DF: 1.52 ± 0.20°, SF: 1.37 ± 0.27°; p = 0.035). Both dynamic and screw fixation groups exhibited significantly reduced plantarflexion during the push-off and early swing phase, with moments and powers in the ankle joint also significantly impaired. Our study demonstrated that dynamic fixation has better or similar biomechanical and clinical outcomes compared to screw fixation. Future research should focus on biomechanical differences during gait as well as clinical outcomes in case of earlier weight-bearing after dynamic fixation. DRKS00013562 Date of Registration: 07/12/2017.

Comparative Study for Surgical Treatment of Acute Distal Tibiofibular Syndesmotic Lesions Using the Modified Suture-Button Fixation Versus Static Syndesmotic Screw Fixation.

Several techniques to treat acute distal tibiofibular instability are described consisting in static and dynamic fixation procedures. The aim of our work is to compare the outcomes of acute syndesmotic injury fixation between the modified technique of dynamic fixation using the suture-button principle as an efficient and low-cost method and the classic static fixation. It is a prospective study including patients presenting with acute syndesmotic injury. After fracture fixation, residual syndesmotic instability was managed using syndesmotic screw in group A and dynamic fixation with a double Ethibond suture in group B. Functional results were assessed using the American Orthopaedic Foot and Ankle Society score (AOFAS) score. Radiological evaluation was done by a postoperative computed tomography (CT) scan of both ankles and plain X-rays of the ankle after surgery and at 18 months. Group A included 20 patients meanwhile 35 patients were in group B. The reduction was satisfactory in the 2 groups according to the postoperative CT scan measurements. The mean healing time in group A was 49.65 days and 51.49 days in group B (P = .45). We did not find any significant difference in terms of loss of reduction in the 2 groups. The return to work was faster in group B (P = .04). Patients in group B had better AOFAS score (P = .03) and ankle range of motion than those in group A. The difference was statistically significant (P = .02 for dorsal flexion and P = .001 for plantar flexion). For group A, we did not note any early complications. Meanwhile, 7 patients developed skin complications in group B (P = .03). However, no significant difference was found in terms of late complications. The modified dynamic suture-button fixation remains a therapeutic alternative in low-income countries that could achieve better outcomes than static fixation, with easy postoperative follow-up. Level II.

Long-term efficacy of Waveflex semi-rigid-dynamic-internal-fixation system in delaying intervertebral disc degeneration at adjacent segments and improving spinal sagittal imbalance

The Waveflex semi-rigid-dynamic-internal-fixation system shows good short-term effects in the treatment of lumbar degenerative diseases, but there are few long-term follow-up studies, especially for recovery of sagittal balance. Fifty patients with lumbar degenerative diseases treated from January 2016 to October 2017 were retrospectively analysed: 25 patients treated with Waveflex semi-rigid-dynamic-internal-fixation system (Waveflex group) and 25 patients treated with double-segment PLIF (PLIF group). Clinical efficacy was evaluated by Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI). Imaging data before surgery and at 3 months, 1 year, and 5 years postoperatively was used for imaging indicator assessment. Local disc degeneration of the cephalic adjacent segment (including disc height index (DHI), intervertebral foramen height (IFH), and range of motion (ROM)) and overall spinal motor function (including lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), and |PI-LL|) were analysed. Regarding clinical efficacy, comparison of VAS and ODI scores between the Waveflex and PLIF groups showed no significant preoperative or postoperative differences. The comparison of the objective imaging indicators showed no significant differences in the DHI, IFH, LL, |PI-LL|, and SS values between the Waveflex and PLIF groups preoperatively and 3 months postoperatively (P > 0.05). These values were significantly different at 1 and 5 years postoperatively (P < 0.05), and the Waveflex group showed better ROM values than those of the PLIF group (P < 0.05). PI values were not significantly different between the groups, but PT showed a significant improvement in the Waveflex group 5 years postoperatively (P < 0.05). The Waveflex semi-rigid dynamic fixation system can effectively reduce the probability of intervertebral disc degeneration in upper adjacent segments. Simultaneously, patients in the Waveflex group showed postoperative improvements in LL, spinal sagittal imbalance, and quality of life.

Acute Ankle Diastasis Injuries Treated with Dynamic, Static Fixation or Anatomic Repair: A Meta-Analysis and Systematic Review of Comparison Studies.

Acute ankle diastasis injuries are complex and debilitating. These injuries occur when the syndesmotic complex becomes compromised. Treatments of acute syndesmotic injuries include static fixation with screws, dynamic fixation with an elastic device, or anatomic repair of the damaged ligament. However, there is disagreement over which method is most effective. The primary purpose of this study was to compare the 3 treatment methods for acute syndesmotic injuries. A systematic literature search was conducted on Embase and PubMed. Studies that compared at least 2 groups with relevant American Orthopaedic Foot & Ankle Society (AOFAS), Visual Analog Scale (VAS), reoperation rate, and complication (implant failure, implant irritation, and infection) data were analyzed. Statistical analysis for this study was performed using Review Manager 5.4, with a standard p-value of ≤0.05 for statistical significance. Twenty-one studies including a total of 1,059 patients (452 dynamic, 529 static, and 78 anatomic) were included for analysis. Dynamic fixation had significantly higher mean AOFAS scores at 3 months postoperation by 5.12 points (95% confidence interval [CI], 0.29-9.96, p = 0.04) as well as at 1 year postoperation by 4.64 points (95% CI, 1.74-7.55, p = 0.002) than static fixation. Anatomic repair had significantly higher AOFAS scores at 6 months postoperation by 3.20 points (95% CI, 1.06-5.34, p = 0.003) and 1 year postoperation by 1.86 points (95% CI, 0.59-3.14, p = 0.004) than static fixation. Dynamic fixation had significantly higher AOFAS scores at 6 months postoperation by 2.81 points (95% CI, 0.76-4.86, p = 0.007), 12 months postoperation by 3.17 points (95% CI, 0.76-5.58, p = 0.01), and at 2 years postoperation by 5.56 points (95% CI, 3.80-7.32, p < 0.001) than anatomic repair. Dynamic fixation also had a lower VAS score average (favorable), only significant at 12 months postoperation, than static fixation by 0.7 points (95% CI -0.99 to -0.40, p < 0.001). Anatomic repair did not have significant difference in VAS scores compared with static fixation. Anatomic repair had significantly lower VAS scores at 12 months postoperation by 0.32 points (95% CI -0.59 to -0.05, p = 0.02) than dynamic fixation. Dynamic fixation had significantly less implant failures (odds ratio [OR], 0.13, 95% CI, 0.05-0.32, p < 0.001) than static fixation. Anatomic repair was not significantly different from static fixation in the complication metrics. Dynamic fixation and anatomic repair were not significantly different in the complication metrics either. Dynamic fixation had a significantly lower reoperation rate than static fixation (OR, 0.23, 95% CI, 0.09-0.54, p < 0.001). Anatomic repair did not have a significantly different reoperation rate compared with static fixation. However, dynamic fixation had a significantly lower reoperation rate than anatomic repair (OR, 4.65, 95% CI, 1.10-19.76, p = 0.04). Dynamic fixation seems to demonstrate superior early clinical outcomes. However, these advantages become negligible in the long term when compared with alternative options. Dynamic fixation is associated with a lower risk for complications, specifically seen with the decrease in implant failures. This method also presents a significantly lower reoperation rate compared with the other treatment approaches. Apart from showing improved early clinical outcomes in comparison with static fixation, anatomic repair did not have significant distinctions in other metrics, including complications or reoperation rate. Level III. See Instructions for Authors for a complete description of levels of evidence.

Effect of Distal Tibiofibular Destabilization and Syndesmosis Compression on the Flexibility Kinematics of the Ankle Bones: An In Vitro Human Cadaveric Model.

Overcompression of the distal tibiofibular syndesmosis during open reduction and internal fixation of ankle fracture may affect multidirectional flexibility of the ankle bones. Ten cadaveric lower limbs (78.3±13.0 years, 4 female, 6 male) underwent biomechanical testing in sagittal, coronal, and axial rotation with degrees of motion quantified. The intact force (100%) was the force needed to compress the syndesmosis just beyond the intact position, and overcompression was defined as 150% of the intact force. After intact testing, the anterior inferior tibiofibular ligament (AITFL), interosseus membrane (IOM), and posterior inferior tibiofibular ligament (PITFL) were sectioned and testing was repeated. The IOM and AITFL were reconstructed in sequence and tested at 100% and 150% compression. Overcompression of the syndesmosis did not significantly reduce ROM of the ankle bones for any loading modality (P > .05). IOM+AITFL reconstruction restored distal tibiofibular axial rotation to the intact condition. Axial rotation motion was significantly lower with AITFL fixation compared with IOM fixation alone (P < .05). The proximal tibiofibular syndesmosis demonstrated significantly higher motion in axial rotation with all distal reconstruction conditions. As assessed by direct visualization, overcompression of the distal tibiofibular syndesmosis did not reduce ROM of the ankle bones. Distal tibiofibular axial rotation was significantly lower with IOM+AITFL fixation compared with IOM augmentation alone. Distal tibiofibular axial rotation did not differ significantly from the intact condition after combined IOM+AITFL fixation. Dynamic fixation of the distal tibiofibular syndesmosis resulted in increased axial rotation at the proximal tibiofibular syndesmosis. These biomechanical data suggest that inadvertent overcompression of the distal tibiofibular syndesmosis when fixing ankle fractures does not restrict subsequent ankle bone ROM. The AITFL is an important stabilizer of the distal tibiofibular syndesmosis in external rotation. controlled laboratory study.

Long-term Outcome of Isobar TTL System for the Treatment of Lumbar Degenerative Disc Diseases.

The Isobar TTL dynamic fixation system has demonstrated favorable outcomes in the short-term treatment of lumbar degenerative disc diseases (LDDs). However, there is a paucity of extensive research on the long-term effects of this system on LDDs. This study aimed to evaluate the long-term clinical and radiological outcomes of patients with LDDs who underwent treatment utilizing the Isobar TTL dynamic fixation system. The study analyzed the outcomes of 40 patients with LDDs who underwent posterior lumbar decompression and received single-segment Isobar TTL dynamic internal fixation at our hospital between June 2010 and December 2016. The evaluation of clinical therapeutic effect involved assessing postoperative pain levels using the visual analogue scale (VAS) and Oswestry disability index (ODI), both before surgery, 3 months after, and the final follow-up. To determine the preservation of functional motion in dynamically stable segments, we measured the range of motion (ROM) and disc height of stabilized and adjacent segments preoperatively and during the final follow-up. Additionally, we investigated the occurrence of adjacent segment degeneration (ASD). Forty patients were evaluated, with an average age of 44.65 years and an average follow-up period of 79.37 months. Fourteen patients belonged to the spondylolisthesis group, while the remaining 26 were categorized under the stenosis or herniated disc group. The preoperative ROM of the stabilized segment exhibited a significant reduction from 8.15° ± 2.77° to 5.00° ± 1.82° at the final follow-up (p < 0.001). In contrast, there was a slight elevation in the ROM of the adjacent segment during the final follow-up, increasing from 7.68° ± 2.25° before surgery to 9.36° ± 1.98° (p < 0.001). The intervertebral space height (IH) in the stabilized segment exhibited a significant increase from 10.56 ± 1.99 mm before surgery to 11.39 ± 1.90 mm at the one-week postoperative follow-up (p < 0.001). Conversely, there was a notable decrease in the IH of the adjacent segment from 11.09 ± 1.82 mm preoperatively to 10.86 ± 1.79 mm at the one-week follow-up after surgery (p < 0.001). The incidence of ASD was 15% (6/40) after an average follow-up period of 79.37 months, with a rate of 15.38% (4/26) in the stenosis or herniated disc group and 14.29% (2/14) in the spondylolisthesis group; however, no statistically significant difference was observed in the occurrence of ASD among these groups (p > 0.05). The Isobar TTL dynamic fixation system is an effective treatment for LDDs, improving pain relief, quality of life (QoL) and maintaining stabilized segmental motion. It has demonstrated excellent long-term clinical and radiographic results.

Rigid tape dynamic fixation in conservative treatment of acute anterior talofibular ligament tear: A retrospective cohort study.

This study aims to compare results of rigid tape (RT) dynamic fixation and static fixation in conservative treatment of acute anterior talofibular ligament (ATFL) tear. Between September 2021 and December 2021, a total of 91 patients (41 males, 50 females, mean age: 28.5±6.5 years, range, 18 to 40 years) who were diagnosed with ATFL tear and underwent rigid tape (RT) or cast/brace rehabilitation protocol were retrospectively analyzed. The patients were divided into two groups as the RT group (n=36) and the control group (n=55). Follow-up (FU) was performed at six months. Outcomes included pain (Numerical Rating Scale [NRS]), ankle function (American Orthopaedic Foot & Ankle Society [AOFAS] hindfoot score), deviation of center of gravity (DCG), and symptoms after returning to sports. The difference at each time point of pain, AOFAS, DCG and SRS between the two groups was statistically significant (p<0.05 for all). Only one patient at Week 12 in the RT group had pain in the lateral side of the ankle, while 36 patients at Week 12 and 21 patients (18 in the medial side) at FU had pain in the control group. Our study results suggest that RT dynamic fixation can accurately lock the ATFL function and may prevent pseudo-stability, so as to quickly repair injury, restore function, and return to sports earlier.

Chronic syndesmotic instability – Current evidence on management

This review article discusses the current evidence on the management of chronic syndesmotic instability. Conservative treatment has a limited role, and surgical intervention is most commonly reported as the mainstay of treatment, however the literature consists of small case series and descriptions of operative techniques, and thus the evidence base for any treatment is weak. Surgical options include arthroscopic debridement alone, static fixation with cortical screws, dynamic fixation with suture-button devices, and ligamentous repair or augmentation.

Intramedullary osteosynthesis for ankle fractures and distal tibiofibular syndesmotic disruption

Introduction The optimal surgical approach for malleolar fractures and distal tibiofibular syndesmotic (DTFS) disruption remains controversial. There is no uniform treatment protocol for this type of injury.The objective was to review modern surgical treatments of the pathology and determine the optimal option.Material and methods Articles of French, English, Uzbek, Kazakh, German, Danish, Japanese and Chinese authors were retrospectively reviewed. An internet search of MedLine; PubMed; Scopus; Web of Science, CINAHL, the Cochrane Central Register of Controlled Trials databases was performed.Results Comparative studies of dynamic fixation and static fixation of the DTFS showed advantages of the dynamic methods enabling precise, anatomical syndesmotic fixation and faster healing. Dynamic fixation methods would require no implant removal, while syndesmotic screw woul be taken off to reduce compression in the ankle joint and minimize a risk of malreduction facilitating mobility of the ankle joint. Dynamic methods are associated with greater stability and less complication rate. However, static methods have the advantages of being more accessible and less expensive, which can be an important factor choosing a treatment method. Static methods are a wide application and can be used in a wide range of clinical cases. Long-term results show no statistically significant differences between dynamic fixation and static fixation.Discussion Literature review indicates the dynamic method with suture-button, a combined method and titanium cable isotonic annular fixation system as the preferred technique for surgical stabilization of distal syndesmosis associated with ankle fractures with a lower risk of postoperative complications and the possibility of short-term rehabilitation.Conclusion The choice between dynamic and static methods of distal syndesmosis fixation depends on many factors, including the complexity of the injury, the availability and cost of implants and the experience of the surgeon.

A Biomechanical Comparison of 2 Different Topping-off Devices and Their Influence on the Sacroiliac Joint Following Lumbosacral Fusion Surgery.

Interspinous spacer (ISS)-based and pedicle screw-rod dynamic fixator (PDF)-based topping-off devices have been applied in lumbar/lumbosacral fusion surgeries for preventing the development of proximal adjacent segment degeneration. However, little attention has been paid to sacroiliac joint (SIJ), which belongs to the adjacent joints. Accordingly, the objective of this study was to compare how these 2 topping-off devices affect the SIJ biomechanics. A validated, normal finite-element lumbopelvic model (L3-pelvis) was initially adjusted to simulate interbody fusion with rigid fixation at the L5-S1 level, and then the DIAM or BioFlex system was instrumented at the L4-5 level to establish the ISS-based or PDF-based topping-off model, respectively. All the developed models were loaded with moments of 4 physiological motions using hybrid loading protocol. Compared with the rigid fusion model (without topping-off devices), range of motion and von-Mises stress at the SIJs were increased by 23.1%-64.1% and 23.6%-62.8%, respectively, for the ISS-based model and by 51.2%-126.7% and 50.4%-108.7%, respectively, for the PDF-based model. The obtained results suggest that the PDF-based topping-off device leads to higher increments in SIJ motion and stress than ISS-based topping-off device following lumbosacral fusion, implying topping-off technique could be linked to an increased risk of SIJ degeneration, especially when using PDF-based device.

Syndesmotic injury with ankle fracture: A systematic review of screw vs dynamic fixation.

Cortical screw fixation across the tibiofibular joint is the mainstay of treatment for syndesmotic injury. Dynamic fixation devices have been developed offering similar advantages to screw fixation in terms of reduction and stability of the syndesmosis. Dynamic fixation may also facilitate a more physiological movement between the tibiofibular joint and thus incur less morbidity. Patient's rehabilitation potential is enhanced and reduces the need for hardware removal.Our systematic review aims to analyse the relevant current literature and compare screw fixation to dynamic fixation in the treatment of syndesmotic injury associated with acute ankle fractures.A literature search was performed on Pubmed and Ovid Medline to find scientific papers relating to syndesmotic fixation in acute ankle fractures. Papers were screened and included dependent on predetermined criteria. Risk of bias was assessed after screening full papers by two independent reviewers. Tables and analysis were made using Microsoft excel.A total of 8 papers with 673 patients were included. We found no functional difference between screw fixation or dynamic fixation groups at final follow-up. Three papers showed statistically significant lower rates of reoperation in the dynamic fixation group.Dynamic fixation may offer lower post operative complications and reoperation rates. Therefore, dynamic fixation may be a beneficial alternative treatment compared to traditionally used syndesmotic screws.

Functional results of patients with ankle syndesmosis injuries treated with the dynamic fixation (the syndesmosis TightRope® suture button) compared to the rigid fixation

Introduction/Objective. Sprains account for 85% of all ankle injuries. Syndesmosis injuries occur in 1?18% of patients with ankle sprains and are more common in contact sports involving forced foot dorsiflexion. Methods. In our study, we compared 30 patients treated with dynamic fixation for acute syndesmotic injury with patients treated with rigid fixation. The criteria for comparison were: American Orthopedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Scale, visual analogue scale (VAS), EuroQol five-dimension questionnaire (EQ-5D), range of motion, complications and reoperations. Results. The mean AOFAS score for patients treated with rigid fixation was 88.6, while the mean score for patients treated with dynamic fixation was 91.6. The mean VAS score for rigid fixation was 83.5, while it was 85.8 for dynamic fixation. Infection as a complication of rigid fixation was present in two patients (11.8%), while it was absent in the dynamic fixation group. The need for implant removal occurred in two patients treated with rigid fixation (11.8%) and in one patient treated with dynamic fixation (7.7%). Conclusion. Based on our results and the results reported by other authors, we prove that there is a lower incidence of problems related to implants and the need for the implant removal with dynamic fixation, based on the results of AOFAS score, we notice better and faster recovery with dynamic fixation as well.

A Modified Dynamic Fixation Technique for Acute Syndesmotic Injuries.

A Modified Dynamic Fixation Technique for Acute Syndesmotic Injuries.

Complex neuroimaging study of the proximal segment after rigid fixation and dynamic stabilization in patients with degenerative lumbar disease

Background. The development of the adjacent level syndrome and, as a consequence, adjacent segment degenerative disease are currently the most common complications of decompression and stabilization surgery with the development of segmental instability. The aim of the study. To conduct a comprehensive neuroimaging assessment of the proximal adjacent segment after rigid fixation and dynamic stabilization in degenerative lumbar disease. Materials and methods. We conducted a prospective multicenter study of the results of surgical treatment of 274 patients with degenerative-dystrophic diseases of the lumbar spine, who underwent monosegmental decompression and stabilization surgery using the TLIF (transforaminal lumbar interbody fusion) technique and open transpedicular rigid fixation, as well as open hemilaminectomy with stabilization of the operated segments with nitinol rods. The study included radiography, diffusion-weighted magnetic resonance imaging and computed tomography (dualenergy mode) of intervertebral discs and isolated facet degeneration of the upper adjacent level. Results and discussion. Combination of the initial proximal segment degeneration in the form of facet joints degeneration (density of cartilaginous plate – 163.5 ± 14.2 HU, density of external facet – 709.35 ± 13.6 HU, density of internal facet – 578.1 ± 12.1 HU), Pfirrmann III, IV grade degeneration of intervertebral disc and a measured diffusion coefficient of less than 1300 mm2/s cause high risks of developing adjacent segment degenerative disease, which regulates the use of monosegmental dynamic fixation with nitinol rods, or preventive rigid fixation of the adjacent segment. Conclusion. Using complex neuroimaging in the preoperative period makes it possible to predict the results of surgical treatment, take timely measures to prevent degenerative diseases of the adjacent segment, and to carry out dynamic monitoring of processes in the structures of the spinal motion segment.

Dynamic Fixation versus Static Screw Fixation for Syndesmosis Injuries in Pronation External Rotation Ankle Fractures: A Retrospective Case Control Study.

The current standard treatment for ankle syndesmosis injury is static screw fixation. Dynamic fixation was developed to restore the dynamic function of the syndesmosis. The purpose of this study was to determine that which of static screw fixation and dynamic fixation is better for treatment of ankle syndesmosis injury in pronation-external rotation fractures. Thirty patients were treated with dynamic fixation (DF group) and 28 patients with static screw fixation (SF group). The primary outcome was Olerud-Molander Ankle Outcome Score. The secondary outcome were Visual Analogue Scale score and American Orthopedic Foot and Ankle Society score, radiographic outcomes, complications and cost effectiveness. To evaluate the radiographic outcome, the tibiofibular clear space, tibiofibular overlap, and medial clear space were compared using the pre-operative and last follow-up plain radiographs. To evaluate the cost effectiveness, the total hospital cost was compared between the two groups. There was no significant difference in primary outcome. Moreover, there were no significant difference in secondary outcome including Visual Analogue Scale score and American Orthopedic Foot and Ankle Society score and radiographic outcome. Two cases of reduction loss and four cases of screw breakage were observed in the SF group. No complication in the DF group was observed. Dynamic fixation was more cost effective than static screw fixation with respect to the total hospital cost. Although dynamic fixation provided similar clinical and radiologic outcome, dynamic fixation is more cost effective with fewer complications than static screw fixation in ankle syndesmosis injury of pronation-external rotation fractures.

Effect of Distal Tibiofibular Syndesmosis Overcompression on the Biomechanical Properties of the Ankle Bones: An In Vitro Cadaveric Model

Category: Trauma; Ankle Introduction/Purpose: Overtightening of the distal tibiofibular syndesmosis during open reduction and internal fixation (ORIF) of ankle fractures remains a clinical concern, and there are limited data delineating the effect of syndesmosis overcompression on subsequent range of motion of the ankle joint bones. The primary objective of the current study was to determine the effect of syndesmotic overcompression on the relative range of motion (ROM) of the tibia, fibula, and talus, and to determine the syndesmotic fixation construct that most accurately restores native motion. Methods: Ten cadaveric lower limbs were utilized (78.3±13.0 yrs, 4F; 6M). A musculoskeletal simulator at ±7.5 Nm was used to test flexibility in dorsiflexion-plantarflexion, inversion-eversion, and internal-external rotation. After intact testing, syndesmotic probes were used to arthroscopically measure the intact position of the distal tibiofibular syndesmosis. The force needed to compress the syndesmosis just beyond the intact position represented the intact force (100%), and overcompression was defined as 150% of the intact force. The anterior inferior tibiofibular ligament (AITFL), interosseus membrane (IOM), and posterior inferior tibiofibular ligament (PITFL) were then sectioned. Testing was repeated for destabilized, IOM reconstruction at 100% compression and 150% overcompression, IOM reconstruction plus AITFL fixation at 100% compression and 150% overcompression, and AITFL fixation alone. ROM data was reported as a percentage of the intact condition. Repeated measures ANOVA and Bonferroni post hoc test were performed to assess differences between conditions with p&lt; 0.05. Results: Average force needed to compress the syndesmosis was 71.0 ± 22.2 N. There was a significant increase in distal tibiofibular ROM in internal and external rotation for all conditions compared to intact (Figure 1) (p &lt; 0.05). In the axial plane, reconstruction of the IOM membrane did not restore the intact condition and was similar to the destabilized treatment, regardless of compression force. The addition of AITFL fixation significantly reduced distal tibiofibular motion compared to IOM reconstructions alone, but still did not approach the intact condition. Overcompression of the syndesmosis did not significantly affect relative ROM of the ankle bones in any plane (p&gt;0.05). Changes in the proximal tibiofibular ROM were similar in magnitude and direction as the distal tibiofibular ROM for all conditions. Conclusion: In the current study, overcompression of the distal tibiofibular syndesmosis did not restrict relative ROM of the tibia, fibula, or talus. Reconstructing the AITFL in addition to the IOM decreased tibiofibular ROM, particularly in the axial plane. In the clinical setting, surgical reconstruction with dynamic fixation of the distal tibiofibular syndesmosis may result in increased ROM and mechanical stress at the proximal tibiofibular articulation.

Varying Distance Between Suture-Endobuttons Does Not Improve Stability of the Transected Syndesmosis in a Motion Tracking Cadaveric Model

Category: Ankle; Sports Introduction/Purpose: A growing body of evidence favors the use of dynamic fixation techniques such as suture endo button over rigid screw fixation for syndesmotic injuries. However, specific dynamic fixation techniques have been poorly evaluated. The purpose of this study was to compare single suture-endobutton fixation (single) to double fixation with suture-endobuttons placed one centimeter (cm) apart (double 1 cm) and double fixation with suture-endobuttons placed three cm apart (double 3 cm). Methods: Twenty-four lower leg specimens from twelve cadavers were tested using a custom biaxial apparatus. Internal rotation, external rotation, and anterior and posterior translation of the tibia and fibula were examined using motion tracking systems after transection of deltoid and syndesmotic ligaments to compare three syndesmotic repair techniques: 1) a single suture-endobutton placed 1 cm above the joint line, 2) two suture suture-endobuttons placed 2 and 3 cm above the joint line, and 3) two suture- endobuttons placed 1 and 4 cm above the joint line. Results: All three endobutton constructs improved the stability of the syndesmosis by reducing aberrant motion after transection. There was no clear superiority of either single suture-endobutton (SEB), double suture-endobuttons placed 2 and 3 cm above the joint line (DSEB 1), or double suture-endobuttons placed 1 and 4 cm above the joint line (DSEB 3). DSEB 3 and DSEB 1 showed equal median laxity for tibia internal rotation (2.7 degrees, DSEB 1 (2.0 – 3.2) degrees, DSEB 3 (2.3 – 2.8) degrees), tibia external rotation (-0.2 degrees, DSEB 1 (-0.4 - 0.4) degrees, DSEB 3 (-0.4 - 0.3) degrees), and fibula external rotation (-0.3 degrees, DSEB 1 (-0.7 - 0.3) degrees, DSEB 3 (-0.7 - 0.7) degrees). Conclusion: Cadaveric biomechanical studies are critical to evaluate various suture-endobutton constructs prior to widespread use in patients. Our results demonstrate that the added cost of a second suture-endobutton may not confer substantial additional stability to the syndesmosis. Likewise, increased spread between suture-endobuttons appears to have minimal impact of syndesmotic stability.

Center-Center Surgical Technique With Dynamic Syndesmosis Fixation: A Cadaveric Pilot Study

The objective of this cadaveric biomechanical study was to evaluate if the center-center surgical technique is a reliable and repeatable method of achieving proper syndesmotic reduction when using dynamic syndesmotic fixation. Nine fresh frozen above-knee cadaveric lower extremities were used. Computerized tomography (CT) scans were first obtained for each intact specimen as the baseline for comparison. A simulated complete syndesmotic disruption was created by transection of all deltoid and syndesmotic ligaments. Instability of the ankle was confirmed with stress imaging using fluoroscopy. Each unstable specimen was repaired using the center-center surgical technique with dynamic syndesmosis fixation. A series of measurements from the axial CT images of intact and repaired specimens were used to determine the anatomic distal tibiofibular relationships for comparison of changes from intact to postfixation. All radiographic measurements were performed by 4 independent foot and ankle surgeons. The level of inter-rater reliability for all the measurements was found to be "moderate" to "excellent" agreement (ICC value: 0.865-0.983, 95% confidence interval: 0.634-0.996). There was no statistical difference found between rotational alignment of native and postfixation (a/b: p=.843; b-a: p=.125; θ: p=.062). There was a statistical difference detected for lateral alignment at the center of fibularis incisura between native and postfixation (average: -0.6 ± 0.8 mm, range: -2.3 to 1.2 mm, p < .001). There was no statistical difference found for the anteroposterior translation alignment between native and postfixation (d/e: p=.251; f: p=.377). This study demonstrated the use of the center-center surgical technique as a viable and repeatable method for achieving anatomical reduction of the tibiofibular syndesmosis when used with dynamic fixation modalities.

Reverse Dynamization Accelerates Regenerate Bone Formation and Remodeling in a Goat Distraction Osteogenesis Model.

This article was updated on December 20, 2023, because of previous errors, which were discovered after the preliminary version of the article was posted online. Figure 4 has been replaced with a figure that presents different p values. Also, on page 1943, the text that had read: "Quantitative microCT confirmed that the total volume of the regenerate in the RD group was much smaller compared with the SF (p = 0.06) and DF (p = 0.007) groups, although it was significantly smaller only compared with the DF group (Fig. 4-A). The total volume of the intact bone (contralateral tibia) was significantly smaller in the RD group compared with the other groups, but the RD group had values closest to those for the intact tibia. Similarly, the RD group had less bone volume compared with the SF and DF groups, and this value was significantly different from the DF group (p = 0.034; Fig. 4-B). Of the 3 groups, the RD group had vBMD that was the closest to that of intact bone. It also had significantly higher vBMD compared with the SF and DF groups (p < 0.0001 for both; Fig. 4-C).The results of torsional testing (Fig. 4-D) confirmed that the regenerate bone formed under conditions of RD was significantly stronger than that formed under SF or DF (p < 0.001 versus SF group, and p = 0.0493 versus DF group)."now reads: "Quantitative microCT confirmed that the total volume of the regenerate in the RD group was significantly smaller compared with the SF and DF groups (p < 0.01 for both groups; Fig. 4-A). The total volume of the intact bone (contralateral tibia) was significantly smaller compared with the SF and DF groups (p < 0.0001 for both). The RD group had values closest to those for the intact tibia, and this difference was not significant (Fig. 4-A). Similarly, the RD group had less bone volume compared with the SF and DF groups, and this value was significantly different from the DF group (p < 0.01; Fig. 4-B). Of the 3 groups, the RD group had vBMD that was the closest to that of intact bone, but the intact bone was significantly different compared with all of the other groups (p < 0.0001 for all groups). The RD group had significantly higher vBMD compared with the SF and DF groups (p = 0.042 and p = 0.046, respectively; Fig. 4-C).The results of torsional testing (Fig. 4-D) confirmed that the regenerate bone formed under conditions of RD was significantly stronger than that formed under SF or DF (p < 0.0001 versus SF group, and p = 0.0493 versus DF group). The intact group was significantly different compared with the SF group (p < 0.0001)."