Sagittal Plane Translation Research Articles

Comparing Multipin Clamps With Outriggers With Standard Clamps for Lower Extremity Periarticular External Fixation: Similar Radiographic and Clinical Outcomes.

Staged treatment of high-energy periarticular tibia fractures involves temporization with closed reduction and external fixation, aiming to provide early reduction and stabilization while mitigating soft-tissue complications. Various external fixator configurations exist, including those that use a "multipin" clamp capable of holding multiple pins but limiting pin placement to a single plane. The purpose of this study was to compare clinical and radiographic outcomes and associated costs of standard and multipin outrigger clamp constructs in tibial plateau and pilon fractures treated with temporary external fixation. We hypothesized that use of the multipin clamp may be associated with poorly aligned reductions and increased complication rates. A retrospective review of 100 patients with periarticular tibial plateau (AO/OTA: 41B/C) or pilon (43B/C) fracture at a Level 1 trauma center from 2014 to 2023 was conducted. Patient, injury, and complication characteristics were collected. Patients were categorized based on the external fixator clamp used: multipin (MP) or standard (S). Clinical outcomes and complication rates were assessed. Radiographic alignment was evaluated by the change in anterior and lateral distal tibial angles, and sagittal plane translation for pilon fractures, and medial and posterior proximal tibial angles for plateau fractures. 70 patients underwent standard (25 pilon, 45 plateau) and 30 multipin (10 pilon, 20 plateau) external fixation. MP and S groups showed no notable differences in demographics or injury characteristics. Both groups demonstrated comparable complication rates and radiological alignment outcomes, with no notable differences observed. MP constructs were more costly than standard systems. In this retrospective study of 100 patients, there was no difference in radiographic or clinical outcomes between the standard frame and multipin frame groups. Typical costs for the multipin frame constructs were $635 to $1249 more than the standard frame constructs.

Not All Proximal Humerus Fractures Do Well Without Surgery: Anterior Translation Predicts the Need for Surgery.

To evaluate the effect of translation on a large series of low energy proximal humerus fractures initially treated nonoperatively. Retrospective multicenter analysis. 5 level-one trauma centers. 210 Patients (152F;58M) average age 64 with 112 left and 98 right sided low energy proximal humerus fractures (OTA/AO 11-A-C). All patients were initially treated nonoperatively and were followed for an average 231 days. Radiographic translation in the sagittal and coronal planes was measured. Patients with anterior translation were compared to those with posterior or no translation. Patients with ≥80% anterior humeral translation were compared to those with < 80% anterior translation, including those with no or posterior translation. The primary outcome was failure of nonoperative treatment resulting in surgery and the secondary outcome was symptomatic malunion. Nine patients (4%) had surgery, 8 for nonunion and 1 for malunion. All 9 patients (100%) had anterior translation. Anterior translation as compared with posterior or no sagittal plane translation was associated with failure of nonoperative management requiring surgery (p = 0.012). Additionally, of those with anterior translation, having ≥80% anterior translation as compared with < 80% was also associated with surgery (p = 0.001). Finally, 26 patients were diagnosed with symptomatic malunion, of whom translation was anterior in 24 and posterior in 2 (p = 0.0001). In a multicenter series of proximal humerus fractures anterior translation of >80% was associated with failure of nonoperative care resulting in non-union, symptomatic malunion, and potential surgery.

A comparison of two immobilization methods in the conservative treatment of pediatric distal forearm fractures: Long arm cast versus single sugar-tong splint.

The aim of this study was to compare the results of single sugar-tong splint (SSTS) and long arm cast (LAC) as an immobilization method in pediatric distal forearm fractures. Between January 2016 and December 2019, a total of 186 pediatric patients (143 males, 43 females; mean age: 10.3±3 years; range, 4 to 15 years) with distal forearm fractures were retrospectively analyzed. The patients were divided into two groups according to the immobilization method: SSTS group (n=74) and LAC group (n=112). All patients were evaluated at the time of admission, immediately after the reduction, and at one, two, and four weeks. Sagittal and coronal plane angulations and translation percentages of the radius at each visit were calculated. Alterations in coronal angle, sagittal angle, sagittal translation and coronal translation were calculated by subtracting the measurements after reduction from the measurements at four weeks. Both groups were comparable in terms of demographic characteristics, fracture localization, and side of injured extremity. There was a statistically significant difference only in the sagittal angulations in the first (LAC: 4.7; SSTS: 6.5; p=0.009) and second week (LAC: 5.3; SSTS: 6.8; p=0.024). The rest of radiological measurements were comparable. In the LAC group, seven patients had re-intervention (three manipulations, four surgeries) and in the SSTS group, three patients had re-intervention (two manipulations, one surgery) (p=0.657). Our study results suggest that SSTS and LAC are comparable in terms of radiological results and need for re-intervention as an immobilization method of pediatric distal forearm fractures.

Comparison of a Novel Modified All-Suture Construct versus Suspensory Suture-button Fixation in a Syndesmotic Injury Model.

To biomechanically investigate a novel modified all-suture construct compared with commercially available suspensory button fixation for stabilization of the syndesmosis. Eight matched pairs of cadaver lower limbs were obtained. We used a material testing machine and Optotrak optoelectronic 3D motion measurement system for testing. Syndesmotic injuries were simulated, and specimens were fixed with either a suspensory suture button or modified all-suture construct. Repaired specimens were then cyclically loaded for 500 cycles. Spatial relationship of the tibia and fibula were continuously monitored for the intact, destabilized, and repaired states. The results were analyzed using independent samples t test. There was no significant difference in sagittal or coronal plane translation between intact and either repair. Compared with the intact state, both repair techniques demonstrated significantly more external rotation of the fibula relative to the tibia and decreased construct stiffness. Cycling of the specimens did not significantly increase coronal or sagittal plane translation; however, external rotation of the fibula relative to the tibia increased and stiffness decreased with cycling for both repair techniques. Our data suggest that sagittal and coronal plane translation is no different from the intact state for both fixation techniques. However, rotation of the fibula relative to the tibia was increased, and construct stiffness was decreased compared with the intact state for both fixation techniques. These findings suggest that an all-suture construct could offer syndesmotic fixation comparable with proprietary suspensory button fixation in a cadaver model.

Blocking Screw Technique for Maintaining Reduction during Intramedullary Screw Fixation of Oblique Metacarpal Fractures.

Intramedullary screw fixation provides a less-invasive means of surgically managing metacarpal fractures. While there are advantages to using this technique compared to CRPP and ORIF, disadvantages of intramedullary screw fixation include loss of reduction intraoperatively due to sagittal and coronal plane translation. The blocking screw technique has been previously described as a solution for this problem in intramedullary fixation of long bone fractures. We describe the blocking screw technique as applied to aid intramedullary screw fixation of metacarpals.

Comparison of the biomechanical stability of transverse and oblique screw trajectories in retrograde intramedullary nailing of supracondylar femur fractures.

The goal was to determine the effect of addition of oblique trajectory distal interlock screws to a retrograde intramedullary femoral nail on implant stability (stiffness), cycles to failure and mode of failure. The hypothesis was that addition of oblique screws would increase implant stability and number of loading cycles to failure. Eight matched pairs were tested; one femur implanted with a femoral nail with only transverse distal interlock screws and the other with transverse and oblique interlock screws. Axial compressive load was applied to the femoral head and the gluteal tendon was tensioned vertically to simulate standing or at 45° to the sagittal plane to simulate stair climbing. Loads were cycled to increasing amplitude until failure of fixation (10mm displacement or 10° rotation). In simulated standing, oblique screw specimen had greater sagittal bending (bowing) than transverse only specimen. Transverse (axial) plane motion was higher in simulated stair climbing in oblique screw specimen. Oblique screw specimen had higher sagittal plane translation at 600N of load. At 300N, oblique screw specimen had lower internal-external rotation than transverse only specimen. A larger number of cycles to failure were observed in four oblique screw of seven paired specimen. Failure (10mm or 10 degrees of motion) was only achieved during simulated stair climbing. Our hypothesis that adding oblique screws improves fixation was rejected. Activities of daily living other than standing may constitute a challenge to fracture fixation; fixation failure occurred at lower loads in simulated stair climbing than standing.

Portable Ultrasound Equals Arthroscopy for Assessment of Syndesmotic Instability

Category: Ankle; Arthroscopy Introduction/Purpose: Syndesmotic instability, when subtle, can be challenging to diagnose-and often requires visualization of the syndesmosis during applied stress. Portable ultrasonography is increasingly used to evaluate ankle instability at the point of care. This study aims to evaluate 1) whether portable ultrasonography (P-US) can diagnose syndesmotic instability in the sagittal plane, and 2) how P-US measurements compare to arthroscopic evaluation. Methods: Eight fresh, above-knee cadaveric specimen were used. The syndesmosis was evaluated with P-US and arthroscopy in the intact state, and thereafter with progressive sectioning of, 1) anterior-inferior tibiofibular ligament (AITFL), 2) interosseous ligament (IOL), and 3) posterior-inferior tibiofibular ligament (PITFL). Sagittal plane translation was simulated with 100N of anterior to posterior (A to P) and posterior to anterior (P to A) directed force using a bone hook. Separately, a 50N manual force was applied to the fibular tip and measured with P-US to simulate a fibular 'shuck test' performed in the clinical setting. Results: When all three syndesmotic ligaments were transected, there was a significant increase in fibular motion in the sagittal plane when evaluated using portable ultrasonography with application of 50N of manual pressure and when applying a 100N hook test when measuring total sagittal plane motion (p=&lt;0.001 and p=0.009). Arthroscopy demonstrated significant increased motion with a 100N hook test when measuring total sagittal plane motion (p&lt;0.001). Conclusion: P-US performed similarly to arthroscopy when diagnosing syndesmotic instability in the sagittal plane. P-US also offers several advantages over arthroscopy, including availability, non-invasiveness, low cost, and affording contralateral comparison. The promise of this technique suggests it should be further explored as a potential future standard for the diagnostic assessment of occult syndesmotic instability in the sagittal plane.

Posterior cruciate-retaining total knee arthroplasty exhibits small kinematic changes in the first postoperative year.

Fluoroscopic knee kinematics have historically been quantified at least 1year after total knee arthroplasty (TKA). The purpose of this study was to longitudinally assess knee kinematics at 6-12weeks, 6months, and 1year after TKA to determine if earlier evaluation may be justified. Twenty-one patients participated after undergoing TKA with a posterior cruciate ligament-retaining fixed-bearing prosthesis. Fluoroscopic examinations of lunge, kneel, and step-up activities were performed at 12 ± 4weeks (V1), 7 ± 2months (V2), and 13 ± 2months (V3) postoperatively. Images were analyzed using a three-dimensional to two-dimensional image registration technique. Maximum flexion poses for lunging and kneeling were compared between visits with repeated-measures statistical tests. For the step-up activity, mixed-effects linear models were constructed for condylar anteroposterior (AP) contact points and tibial internal rotation throughout flexion. Estimated marginal means of fitted values were plotted with 95% confidence intervals and used to compare mean kinematics between visits. There were no significant changes in maximum lunging flexion over time (p = 0.405), though significant increases in maximum kneeling flexion were observed between V1 (106 ± 8°) and V2 (110 ± 9°) (p = 0.006), and V1 and V3 (113 ± 9°) (p = 0.0003). While statistical differences were calculated for lunging medial condyle AP translation and kneeling tibial internal rotation, absolute differences in condylar AP contact locations were less than ~ 2mm between all visits during both movements. For the step-up activity, tibial internal rotation increased with flexion, and there were pair-wise significant differences at all flexion angles between V1-V2 (p < 0.001) and V1-V3 (p < 0.001). Anterior medial condylar translation was observed with flexion, with pair-wise significant differences present for V1-V3 (p = 0.005) and V2-V3 (p < 0.001). The lateral condyle exhibited initial posterior translation followed by anterior translation with increasing flexion, with pair-wise differences between all visits (p < 0.005 for all comparisons). Though statistical differences were observed between visits for all activities, variations in estimated mean condylar positions were within ~ 2mm from ~ 12weeks to 1year. Considering measurement error averages approximately 1mm for sagittal plane translations, these results indicate that knee kinematics during kneel, lunge, and step-up activities may be sustained from as early as 12weeks after TKA.

Isolated injuries to the lateral ankle ligaments have no direct effect on syndesmotic stability.

This study aim was to detect the impact of lateral ankle ligaments injury on syndesmotic laxity when evaluated arthroscopically in a cadaveric model. The null hypothesis was that lateral ankle ligament injury does not affect the stability of syndesmosis. Sixteen fresh-frozen above-knee amputated cadaveric specimens were divided into two groups of eight specimens that underwent arthroscopic evaluation of the distal tibiofibular joint. In both the groups, the assessment was first done with all syndesmotic and ankle ligaments intact. Thereafter, Group 1 underwent sequential transection of the three lateral ankle ligaments first to identify the effects of lateral ligament injury: (1) anterior talofibular ligament (ATFL), (2) calcaneofibular ligament (CFL), (3) posterior talofibular ligament (PTFL), then followed by the syndesmotic ligaments, (4) AITFL, (5) Interosseous ligament (IOL), and (6) PITFL. Group 2 underwent sequential transection of the (1) AITFL, (2) ATFL, (3) CFL, (4) IOL, (5) PTFL, and (6) PITFL, which represent the most commonly injured pattern in ankle sprain. In all scenarios, four loading conditions were considered under 100N of direct force: (1) unstressed, (2) a lateral fibular hook test, (3) anterior to posterior (AP) fibular translation test, and (4) posterior to anterior (PA) fibular translation test. Distal tibiofibular coronal plane diastasis at the anterior and posterior third of syndesmosis, as well as AP and PA sagittal plane translation, were arthroscopically measured. The distal tibiofibular joint remained stable after transection of all lateral ankle ligaments (ATFL, CFL, and PTFL) as well as the AITFL. However, after additional transection of the IOL, the syndesmosis became unstable in both the coronal and sagittal plane. Syndesmosis laxity in the coronal plane was also observed after transection of the ATFL, CFL, AITFL, and IOL. Subsequent transection of the PITFL precipitated syndesmosis laxity in the sagittal plane, as well. The findings from the present study suggest that lateral ankle ligament injuries itself do not directly affect the stability of syndesmosis. However, if it combines with IOL injuries, even partial injuries cause syndesmotic laxity. As a clinical relevance, accurate diagnosis is the key for surgeons to determine syndesmosis fixation whether there is only AITFL injury or combined IOL injury in concomitant acute syndesmotic and lateral ligament injury.

Kinematically Aligned Total Knee Arthroplasty Using Medial Pivot Knee Prosthesis Enhances Medial Pivot Motion: A Comparative Kinematic Study With Mechanically Aligned Total Knee Arthroplasty.

BackgroundClinical outcomes of kinematically aligned total knee arthroplasty (KA-TKA) have been reported as comparable or superior to those of mechanically aligned TKA (MA-TKA). However, cruciate-retaining prostheses have mostly been used for KA-TKA. This study used medial pivot knee prostheses for KA-TKA, and knee kinematics after KA-TKA were assessed and compared with those after MA-TKA.MethodsThirteen knees in 9 patients undergoing primary TKA (8 KAs, 5 MAs) were subjected to two-dimensional (2D) to three-dimensional (3D) registration analysis at 1 year postoperatively. Each patient performed weight-bearing activities, and movements were recorded as intermittent digital radiographic images. Three-dimensional implant positions during activities were analyzed for anterior-posterior translation in the sagittal plane, condylar liftoff and mediolateral translation in the coronal plane, and femoral rotation in the axial plane.ResultsPosterior translation of the lateral femoral condyle from 0° to 100° was larger in KA-TKA than in MA-TKA (P = .006). The degrees of condylar liftoff and mediolateral translation were comparable between TKAs. Total external rotation of the femoral component relative to tibial component was significantly greater for KA-TKA (7.7 ± 5.2°) than for MA-TKA (1.3 ± 3.3°; P = .03). The kinematic path of the femoral component revealed greater medial pivoting motion in KA-TKA than in MA-TKA.ConclusionsKA-TKA using a medial pivot knee prosthesis successfully reproduced the medial pivot pattern and achieved larger femoral external rotation relative to the tibia than MA-TKA. KA-TKA was able to maximize the primary concept of the medial pivot knee prosthesis.

Correction outcomes of the postoperative malalignment salvaged by the temporary application of the hexapod external fixator in tibial diaphyseal fractures treated by monolateral external fixation

BackgroundPostoperative malalignment in fractures treated by monolateral external fixation is not uncommon in clinical practice. Accurate reduction without excessive tissue disruption caused by surgical intervention and sequentially manage the fractures using monolateral external fixation for definitive treatment is still a challenge for surgeons. The purpose of our study was to evaluate the feasibility and effectiveness of the temporary application of the hexapod external fixator (HEF) for the postoperative malalignment correction in tibial diaphyseal fractures treated by monolateral external fixation. MethodsWe carried out a retrospective analysis of 23 trauma patients with tibial diaphyseal fracture treated by the monolateral external fixation at our institution from January 2016 to May 2019. There were 21 males and 2 females with a mean age of 38 years (range 18-60 years). The hexapod external fixator was temporarily applied due to postoperative malalignment within two weeks and who unwilling to undergo a secondary surgical intervention. For patients with postoperative malalignment requiring correction, the HEF components were installed on the original existing half pins of the monolateral external fixator after removing the connecting rod. The standard anteroposterior and lateral X-rays of the injured limb combined with the temporary HEF were conducted to measure the hexapod external fixator parameters. Any residual deformities were corrected by gradual struts adjustment with the aid of computer-based software. When satisfactory alignment was achieved, the HEF was removed, and the monolateral external fixator was sequentially used as the definitive structure. ResultsAll patients acquired functional reduction, which was evaluated by radiographs. The mean correction time was 4 days (range 2 to 8 days). The mean coronal plane translation (1.3±1.0 mm), coronal plane angulation (0.9±0.7°), sagittal plane translation (1.4±1.1 mm), and sagittal plane angulation (0.7±0.7°) after correction were all less than those (7.0±4.9 mm, 4.7±2.3°, 5.6±3.6 mm, 3.2±2.5°) before correction. ConclusionsThe temporary application of the hexapod external fixator is an alternative and feasible method for the postoperative malalignment correction in tibial diaphyseal fractures treated by monolateral external fixation.

Subcapital phalangeal fractures in children: A retrospective review

Introduction: Phalangeal neck fractures represent a subset of pediatric hand injuries which pose challenges to the treating physician. The aim of this study was to understand which radiographic or clinical variables were associated with the need for closed reduction and percutaneous pinning or were associated with the need for open reduction internal fixation. Methods: A retrospective review was performed on pediatric patients treated for subcapital phalangeal neck fracture of the middle or proximal phalanx between 2009 and 2014. Non-operative and operative groups (open reduction internal fixation, closed reduction percutaneous pinning) compared displacement and angulation of the distal fragment at the time of initial injury, displacement, and angulation of the distal fragment at the time of final follow-up, mechanism of injury, delays in treatment, time to union, and rate of complications. Results: One hundred seventy seven patients met eligibility criteria for the review. Average age was 9.1 years for the surgical group and 8.5 years for the non-surgical group. Time to union was significantly higher for the surgery group (53 vs 30 days, p &lt; 0.001). The degree of sagittal plane translation and sagittal angulation were predictive factors for surgical treatment. Sagittal plane angulation was higher in the surgical group (26.5° vs 9°, p &lt; 0.001). A delay in treatment with subsequent surgery was not predictive of a need for open reduction internal fixation over closed reduction percutaneous pinning ( p = 0.19). Final sagittal angulation was corrected to a median of zero, an eight degree difference from the non-surgical group ( p = 0.002). Conclusions: This study demonstrates that a strong correlation between initial sagittal plane angulation and a need for surgery. A longer time to union and decreased range of motion may be expected in patient's requiring operative intervention. Delay in treatment was not associated with open reduction over closed reduction percutaneous pinning within the surgical group.

Application of elliptic registration and three-dimensional reconstruction in the postoperative measurement of Taylor spatial frame parameters

BackgroundThe Taylor spatial frame offered the ability of simultaneous correction of the multidirectional deformities without the need to change the frame, and it was widely used for limb lengthening, deformity correction, and fracture reduction in recent years. There are still some inherent limitations that can affect the accuracy of correction, especially for the measurement of the mounting and rotational parameters. The purpose of our study was to propose some more precise postoperative measurement of Taylor spatial frame (TSF) parameters by application of elliptic registration and three-dimensional reconstruction. MethodsThis retrospectively study included 28 trauma patients who suffered tibial fracture treated by the TSF at our institution from January 2016 to January 2018, including 25 males and 3 females with a mean age of 43 years (range 14-70 years). We conducted standard full-length anteroposterior and lateral X-rays of the injured extremity and the computed tomographic scans of the bilateral extremities after the operation. Elliptic registration and 3D reconstruction were used to calculate the parameters by two types of software Mimics and CorelDRAW. Correction of the deformity was conducted by adjusting the struts of the TSF according to the electronic prescription. The standard anteroposterior and lateral X-rays after correction were taken to evaluate the effectiveness. ResultsAll patients acquired functional reduction, which was evaluated by digital radiography. The mean coronal plane translation(1.9±2.2 mm), coronal plane angulation(1.2±1.0°), sagittal plane translation(2.7±2.1 mm), and sagittal plane angulation(1.2±1.0°) after correction were all less than those(5.5±4.6 mm, 4.9±3.9°, 4.7±4.0 mm, 2.7±2.3°) before correction. ConclusionsThe TSF system can correct the 6-axis deformities simultaneously with the accurate parameters. Elliptic registration and three-dimensional reconstruction are alternative methods to precisely measure the parameters needed by the TSF system, especially for the mounting and rotational parameters of unusually complex cases.

Diagnosing Syndesmosis Instability: Dynamic Ultrasound versus Arthroscopy: A Cadaveric Study

Category:AnkleIntroduction/Purpose:To evaluate whether sagittal translation could be detected with ultrasound and arthroscopy and to compare the increasing tibiofibular sagittal translation seen with ultrasound (US) and Arthroscopy.Methods:Eight fresh lower leg cadaveric specimen amputated above the proximal tibiofibular joint were used in this study. The ankle syndesmosis was evaluated using a handheld US device (Butterfly iQ, Butterfly Network Inc, Guilford) and arthroscopy with intact-, and after sequent sectioning of anterior-inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), and posterior- inferior tibiofibular ligament (PITFL). Sagittal plane translation was simulated with 100N of anterior to posterior (A-to-P) and posterior to anterior (P-to-A) hook force which was applied 5cm above of the ankle joint (Figure 1). Pearson’s correlation, one- way repeated measures ANOVA, and Wilcoxon signed-rank test were used for comparison. Three cadavers were measured by two independent observers to assess reliability and analyzed using intraclass correlation coefficients (ICC).Results:A-to-P translation values obtained with US and Arthroscopy had a correlation of -0.14, and P-to-A translation correlation of 0.44. Using US, intact translation was 0.94+-0.62 with A-to-P hook and 0.87+-0.5 with P-to-A hook. Subsequent A- to-P and P-to-A translation increased with 0.07+-0.96mm and 0.04+-0.76 after AITFL cut, with 0.53+-0.9 and 0.15+-0.5 after IOL cut, and with 0.81+-1.3mm and 0.45+-0.8 after PITFL cut (p-values between 0.122 and 0.270) . Using arthroscopy, intact translation was 0.40 +-0.3 with A-to-P hook and 0.99+-0.5 with P-to-A hook. Subsequent A-to-P and P-to-A translation increased from intact with; 0.001+-0.3 and 0.30+-0.4 after AITFL cut, 0.19+-0.4 and 0.74+-0.7 after IOL cut, and 0.40+-0.5 and 1.1+-0.9 after PITFL cut (p-values between 0.005 and 0.037). No statistical differences between US and Arthroscopy were found.Conclusion:US was unable to differentiate between the different stages of injury, even though a similar increase in translation was seen as compared to arthroscopy. Probably this is due to the high variability seen in the US translation values. As US does have several advantages over arthroscopy; availability, non-invasiveness, low costs, and allowance of using the contralateral side as a direct comparison, this technique should be further explored as a potential diagnostic assessment technique of diagnosing occult syndesmotic instability in the sagittal plane.

Arthroscopic Assessment of Syndesmotic Instability in the Sagittal Plane in a Cadaveric Model.

Syndesmotic instability is multidirectional, occurring in the coronal, sagittal, and rotational planes. Despite the multitude of studies examining such instability in the coronal plane, other studies have highlighted that syndesmotic instability may instead be more evident in the sagittal plane. The aim of this study was to arthroscopically assess the degree of syndesmotic ligamentous injury necessary to precipitate fibular translation in the sagittal plane. Twenty-one above-knee cadaveric specimens underwent arthroscopic evaluation of the syndesmosis, first with all syndesmotic and ankle ligaments intact and subsequently with sequential sectioning of the anterior inferior tibiofibular ligament (AITFL), the interosseous ligament (IOL), the posterior inferior tibiofibular ligament (PITFL), and deltoid ligament (DL). In all scenarios, an anterior to posterior (AP) and a posterior to anterior (PA) fibular translation test were performed under a 100-N applied force. AP and PA sagittal plane translation of the distal fibula relative to the fixed tibial incisura was arthroscopically measured. Compared with the intact ligamentous state, there was no difference in sagittal fibular translation when only 1 or 2 ligaments were transected. After transection of all the syndesmotic ligaments (AITFL, IOL, and PITFL) or after partial transection of the syndesmotic ligaments (AITFL, IOL) alongside the DL, fibular translation in the sagittal plane significantly increased as compared with the intact state (P values ranging from .041 to <.001). The optimal cutoff point to distinguish stable from unstable injuries was equal to 2 mm of fibular translation for the total sum of AP and PA translation (sensitivity 77.5%; specificity 88.9%). Syndesmotic instability appears in the sagittal plane after injury to all 3 syndesmotic ligaments or after partial syndesmotic injury with concomitant deltoid ligament injury in this cadaveric model. The optimal cutoff point to arthroscopically distinguish stable from unstable injuries was 2 mm of total fibular translation. These data can help surgeons arthroscopically distinguish between stable syndesmotic injuries and unstable ones that require syndesmotic stabilization.

The arthroscopic syndesmotic assessment tool can differentiate between stable and unstable ankle syndesmoses.

Patients with stable isolated injuries of the ankle syndesmosis can be treated conservatively, while unstable injuries require surgical stabilisation. Although evaluating syndesmotic injuries using ankle arthroscopy is becoming more popular, differentiating between stable and unstable syndesmoses remains a topic of on-going debate in the current literature. The purpose of this study was to quantify the degree of displacement of the ankle syndesmosis using arthroscopic measurements. The hypothesis was that ankle arthroscopy by measuring multiplanar fibular motion can determine syndesmotic instability. Arthroscopic assessment of the ankle syndesmosis was performed on 22 fresh above knee cadaveric specimens, first with all syndesmotic and ankle ligaments intact and subsequently with sequential sectioning of the anterior inferior tibiofibular ligament, the interosseous ligament, the posterior inferior tibiofibular ligament, and deltoid ligaments. In all scenarios, four loading conditions were considered under 100N of direct force: (1) unstressed, (2) a lateral hook test, (3) anterior to posterior (AP) translation test, and (4) posterior to anterior (PA) translation test. Anterior and posterior coronal plane tibiofibular translation, as well as AP and PA sagittal plane translation, were arthroscopically measured. As additional ligaments of the syndesmosis were transected, all arthroscopic multiplanar translation measurements increased (p values ranging from p < 0.001 to p = 0.007). The following equation of multiplanar fibular motion relative to the tibia measured in millimeters: 0.76*AP sagittal translation + 0.82*PA sagittal translation + 1.17*anterior third coronal plane translation-0.20*posterior third coronal plane translation, referred to as the Arthroscopic Syndesmotic Assessment tool, was generated from our data. According to our results, an Arthroscopic Syndesmotic Assessment value equal or greater than 3.1mm indicated an unstable syndesmosis. This tool provides a more reliable opportunity in determining the presence of syndesmotic instability and can help providers decide whether syndesmosis injuries should be treated conservatively or operatively stabilized. The long-term usefulness of the tool will rest on whether an unstable syndesmosis correlates with acute or chronic clinical symptoms.

Biomechanical Comparison of Syndesmotic Repair Techniques During External Rotation Stress

The purpose of this study was to compare mechanical behavior of conventional syndesmosis fixation devices with new anatomic repair techniques incorporating various repair augmentations to determine which approach would return rotational ankle mechanics closer to those of an intact ankle. Ten pairs of fresh-frozen through-the-knee cadaveric lower limbs were subjected to 7.5 Nm of external rotation torque while under 750 N of axial compression. After testing specimens intact and with the deltoid and syndesmotic ligament complexes completely destabilized, specimens underwent syndesmotic fixation using a screw, a suture button construct, a prototype structurally augmented flexible trans-syndesmotic fixation device, or the prototype device plus suture repairs of the anterior-inferior tibiofibular ligament and deep deltoid ligament. Syndesmotic repair devices were exchanged between tests so that each specimen was tested with 2 different fixation techniques. Whole-foot rotation angles at 7.5 Nm of applied torque were measured for comparison of the different repair strategies, and reflective markers mounted on the tibia, fibula, and talus were used to track translations and rotations of the talus and the fibula relative to the tibia during testing. Syndesmotic destabilization significantly ( P < .001) increased whole-foot, talus, and fibula rotation in an axial plane and posterior fibula translation under 7.5 Nm of torque. Neither the suture button nor the augmented flexible trans-syndesmotic fixation device reduced those increases. Screw fixation or addition of anatomic ligament repairs to the augmented flexible fixation device successfully reduced axial plane rotations and sagittal plane translations to near intact levels. Flexible trans-syndesmotic fixation alone was found to be insufficient for restoring rotational stability to the ankle/talus or preventing sagittal plane displacement of the fibula. Repairs to simulate anatomic structures disrupted during a syndesmosis injury were required to restore rotational stability to the foot when using flexible trans-syndesmotic fixation that may have clinical applicability.

Changes in Sagittal Alignment After Cervical Disc Arthroplasty: Results of 24 Month Pilot Study

Background Context: For cervical disc replacements to be comparable to the gold standard of cervical discectomy and fusion (ACDF), disc replacements they must be able to provide normal range of motion as well as predictable and reliable correction of cervical alignment. The Synergy Disc was designed to provide correction of alignment in the sagittal plane while restoring physiologic range of motion. Purpose: This study evaluated whether the Synergy Disc provided preservation and/or restoration of sagittal alignment while normalizing kinematics and providing acceptable clinical outcomes. The alignment provided by the Synergy Disc was compared with a retrospective cohort of 30 single- level ACDF patients. Study Design/Setting: The pilot trial was a multi-center, prospective, consecutive patient enrollment study using the Synergy Disc for the treatment of single and two-level degenerative disc disease of the cervical spine. Patient Sample: The procedure was performed on 43 patients (45 implants) with follow-up on 40 patients (42 implants). For the historical cohort ACDF arm, 30 patients with similar follow-up with single level anterior discectomy, fusion and plating were used for segmental lordosis measurements. Outcome Measures: For the Synergy Disc group, the kinematic outcome parameters included: range of motion (ROM), shell angle (SA), disc height (DH), sagittal plane translation and center of rotation (COR) in the X and Y direction. Standard assessments of clinical outcomes were also measured (Neck Disability Index, Visual Analog Scale). For the fusion arm, only functional spinal unit (FSU) angle was recorded using a single preoperative and postoperative standing lateral cervical radiograph. Methods: In the Synergy Disc group, static and dynamic radiological assessments were performed in 43 consecutive patients prior to the placement of the Synergy Disc. Forty patients were studied for the course of the study protocol (3 patients lost to follow-up). For the Synergy Disc group, lateral cervical radiographs were evaluated for range of motion, translation, center of rotation, disc height and shell angle before and at the longest postoperativr follow-up. Neck Disability Index and Visual Analog Scale for arm and neck pain were collected and analyzed. For the fusion group, standing lateral radiographs were reviewed. Results: In all the patients (40 patients, 42 implants), followed up for at least 24 months at an average of 28 months the average SA of the Synergy Disc was maintained at 6±2.7° of lordosis. Preoperative ROM, translation and center of rotation on X axis did not change significantly following surgery. There was a significant upward shift in the center of rotation on Y axis. There was significant improvement in all clinical outcome measures. In the fusion group, with a similar follow-up period, there was a 4° increase in lordosis at the FSU. Conclusions: The Synergy Disc provided lordosis at the surgical level, while maintaining preoperative range of motion, translation and COR X. The lordosis of 6±2.7° provided by the Synergy Disc at 2 years following surgery was comparable to the lordotic correction provided by an anterior cervical discectomy with interbody fusion and plating.

Rater reliability and construct validity of a mobile application for posture analysis.

[Purpose] Measurement of posture is important for those with a clinical diagnosis as well as researchers aiming to understand the impact of faulty postures on the development of musculoskeletal disorders. A reliable, cost-effective and low tech posture measure may be beneficial for research and clinical applications. The purpose of this study was to determine rater reliability and construct validity of a posture screening mobile application in healthy young adults. [Subjects and Methods] Pictures of subjects were taken in three standing positions. Two raters independently digitized the static standing posture image twice. The app calculated posture variables, including sagittal and coronal plane translations and angulations. Intra- and inter-rater reliability were calculated using the appropriate ICC models for complete agreement. Construct validity was determined through comparison of known groups using repeated measures ANOVA. [Results] Intra-rater reliability ranged from 0.71 to 0.99. Inter-rater reliability was good to excellent for all translations. ICCs were stronger for translations versus angulations. The construct validity analysis found that the app was able to detect the change in the four variables selected. [Conclusion] The posture mobile application has demonstrated strong rater reliability and preliminary evidence of construct validity. This application may have utility in clinical and research settings.

MRI of Sagittal Plane Translation of Cervical Vertebrae With Graded Central Posterior-Anterior (CPA) Mobilization

MRI of Sagittal Plane Translation of Cervical Vertebrae With Graded Central Posterior-Anterior (CPA) Mobilization