Category:
Ankle; Sports
Introduction/Purpose:
Lateral ankle sprains are the most frequent ankle trauma and may lead to chronic lateral ankle instability (CLAI). Studies have reported anterior ...talofibular (ATFL) and calcaneofibular (CFL) ligaments tensile strengths around 200N and 300N. Cone Beam Weight Bearing CT (WBCT) allows visualization of 3D bony anatomy in different functional positions. The primary objective of this study was to calculate 3D ATFL and CFL tensile loads in patients diagnosed with CLAI performing Forced Inversion stance during WBCT imaging (FI-WBCT) and wearing shoes, and to compare them with a population of non-CLAI ankles. The secondary objective was to evaluate the relative contribution of shoes. We hypothesized that ATFL and CFL calculated tensile loads (CTLs) would be close to previously published data with minimal contribution of shoes.
Methods:
This retrospective comparative Level III study included 20 CLAI ankles and 20 controls with known demographics and available FI-WBCT datasets. Patients under 18 or with a previous history of trauma or surgery which could affect ankle architecture were excluded. A mechanical lever arm model was calculated for each case using the spatial coordinates of the weight bearing surfaces of the shoe and foot (bony landmarks: 5th metatarsal head, base and calcaneus lowest points, distal tip of the medial malleolus, ATFL and CFL distal insertion points, distal tip of the fibula). The ATFL and CFL CTL were calculated respectively as the coronal force applied at the distal insertion landmarks of the ATFL on the talus and CFL on the calcaneus. Normality was assessed using the Shapiro-Wilk test, then variables were compared using the Student t-test (normally-distributed) or the Wilcoxon rank sum test (non normally-distributed variables). Chi-2 was used for categorical variables.
Results:
Mean age 42.4+-10.9 vs 40.8+-10.7 years; p=0.317, Body Mass Index 24.4+-3.3 vs 24.9+-4 kg.m-2; p=0.34, sex (p=0.75), side (p=0.75) and foot alignment (FAO -1.05%+-5.5 vs 0.08%+-3.6; p=0.22) were not different between CLAI ankles and controls. CTLs for ATFL were 194N+-149 in CLAI and 192N+-183 in controls (p=0.85), while for CFL they were 311N+-286 and 311N+-361, respectively (p=0.79). Using footwears, CTLs were 406N+-360 in CLAI vs 608N+-380 in controls (p<0.05) for ATFL, and 703N+-741 vs 958N+-779 (p=0.11) for CFL. Comparing barefoot and shod values, mean CTLs in the ATFL (193N+-164.8 vs 507N+-379.1, respectively; p<0.001) and in CFL (311.3N+-321 vs 830.8N+-761.5, respectively; p<0.001) were significantly different.
Conclusion:
We found that the Calculated Tensile Loads for ATFL and CFL using Forced Inversion-WBCT considering the barefoot weightbearing surface were close to values described in previous cadaveric studies for those ligaments' tensile strength. A 2.6 and 2.7 fold increase was found when the weight bearing surface of the shoe was considered, indicating a possible aggravating role of shoewear. The reduced shod ATFL-CTL values found in unstable cases as compared to controls could suggest a possible active self-protection mechanism during FI-WBCT in CLAI.
Category:
Trauma
Introduction/Purpose:
Methods of fixation in ankle fractures involving the posterior malleolus have become increasingly scrutinized. With the increase in computed tomography (CT), an ...intercalary fracture fragment (ICF) adjacent to the posterior malleolus has often been described. Treatment of this intercalary comminution remains controversial. The primary goal of this study was to compare clinical and radiographic outcomes in patients who had direct reduction and fixation of this fragment compared to those where the ICF was removed or not reduced prior to posterior malleolus fixation.
Methods:
This retrospective study included 249 trimalleolar and posterior pilon ankle fractures grouped into those who had the ICF reduced and fixed (n=74) and those where the ICF was not directly addressed or excised (n=175). CT scans were evaluated for size and location of the ICF. Demographic, radiographic and intraoperative variables were collected and analyzed. The Kellgren and Lawrence classification system was utilized to grade severity of post-traumatic arthritis during the follow up period. Chart review was performed assessing time to weightbearing, repeat surgeries and post-operative complications.
Results:
For the group which had the ICF reduced and fixed, follow up radiographs demonstrated significantly worse Kellgren- Lawrence scores compared to the group that did not specifically reduce the ICF (p< 0.05). There was also a higher rate of repeat surgery in the group which had the ICF fixed, although not meeting statistical significance. There were no differences in size or location of the ICF fragment between groups. The average overall time to weightbearing amongst all patients was 9.7 +- 3.8 weeks. There was no significant difference between time to weightbearing between groups (p = 0.6). There was no significant difference in need for secondary surgeries or post-operative deep and superfical infections.
Conclusion:
With the widespread utilization of CT-scans for preoperative planning of ankle fractures involving the posterior malleolus, there has been greater discussion surrounding the optimal management of the ICF when present. In our study, the primary aim was to explore radiographic changes in patients after direct reduction and fixation of this ICF compared to those without ICF fixation. We demonstrated significantly worse radiographic outcomes following attempted direct reduction and fixation of the ICF. Our results suggest that while concentric joint reduction and syndesmosis stabilization are of utmost importance, attempting to reduce and fix the ICF may lead to worse radiographic outcomes.
Category:
Ankle; Basic Sciences/Biologics; Trauma
Introduction/Purpose:
The PUMA System (Panther Orthopedics, Sunnyvale, CA) is an FDA cleared. superelastic, nitinol based fixation device for the ...ankle syndesmosis which provides stabilization without over-compression or loosening due to creep from cyclic loading. Objective The objective of this study was to test resistance to lengthening (creep) of the PUMA System in cyclic fatigue testing.
Methods:
Five PUMA System devices, each having a nitinol Body consisting of six layers, were cycle-tested between 20/40 pounds per cubic foot (lb/ft3) polyurethane foam Bone Blocks (Figure 1).1 The PUMA System devices were set up with an initial device Active Length of approximately 66 millimeters (mm) between their polyether ether ketone (PEEK) Anchor buttons. All devices were tightened to a minimum of 11.1 Newtons (2.5 pounds force) and cycled at 5 cycles per second (5 Hz) for 4500 cycles to 2.4 mm displacement. Device Active Length was recorded pre- and post-testing. Devices were visually inspected for any break in the 30 nitinol layers. 1 ASTM F1839: Standard Specification for Rigid Polyurethane Foam for Use as a Standard Material for Testing Orthopedic Devices and Instruments.
Results:
None of the 30 layers incorporated in the 5 PUMA SystemTM device Bodies failed due to cyclic fatigue. Also, there was little-to-no difference between pre- and post-testing Active Length (Figure 2). More specifically an average increase of only 0.2% in length with a with a Standard Deviation of 0.16% evidences no significant creep (Table 1).
Conclusion:
The PUMA SystemTM allows for ankle syndesmosis repair with an implant that experiences no significant creep as demonstrated in cyclic-fatigue testing under challenging displacement cycle testing.
Category:
Ankle
Introduction/Purpose:
The purpose of this study was to present the surgical technique and to evaluate the clinical and radiological outcomes of a new press-fit OATS technique for ...large primary and secondary talar osteochondral defects of the talus, Talar OsteoPeriostic grafting from the Iliac Crest (TOPIC).
Methods:
Forty patients underwent a press-fit TOPIC procedure. Mean age was 38 years (SD 4.6). Pre- and postoperative clinical assessment at 12- and 24-months follow-up included the American Orthopaedic Foot & Ankle Society (AOFAS) score, the Short- Form 36 (SF-36) Mental Component Scale (MCS) and Physical Component Scale (PCS), the Numeric Rating Scales (NRS) of pain at rest, during walking and stairclimbing, and the Foot and Ankle Outcome Score (FAOS). Return to work was assessed in time and rate. Remodeling of the contour of the talus, bone ingrowth and consolidation of the implanted graft were assessed on computed tomography (CT) one year post-operatively.
Results:
All patients were available for the two-year follow-up. The AOFAS improved from 48 to 90 (p<0.05). All NRS scores improved: the NRS during rest from 3 to 0 (p<0.05), the NRS during walking from 5 to 1 p<0.05), and the NRS during stairclimbing from 5 to 1 (p<0.05). Both components of the SF-36 improved. The PCS improved from 34 to 47 (p<0.05) and the MCS from 37 to 66 (p<0.05). All FAOS subscales significantly improved. 70% returned to sport at pre-injury sports level and mean time to return to sports was 9 months (SD 2.4). All patients showed remodeling of the talus and all grafts showed consolidation as well as bone ingrowth on the CT scans. All patients returned to work, at a mean time of 4 months post-operatively (SD 4.4). One patient had a temporary loss of n. saphenous sensibility.
Conclusion:
The TOPIC procedure is a highly promising surgical treatment option for large primary and secondary talar OCDs. Despite these good mid-terms clinical, sports and radiological outcomes, longer follow-up is necessary to assess the clinical outcome and the progression of osteoarthritis at the long term.
Category:
Other; Ankle Arthritis; Hindfoot; Midfoot/Forefoot
Introduction/Purpose:
Allograft is routinely used to enhance bone healing in foot and ankle surgery. One allograft in particular employs ...viable cells and bone scaffolding in a gel base. There is little evidence that compares how this material effects rate of fusion (ROF) and time to fusion (TTF) when compared to autograft in routine forefoot, midfoot, and hindfoot fusions. Our study investigates the use of a viable cellular allograft and its effect on these two variables in a population of patients undergoing fusions in the foot and ankle.
Methods:
A retrospective review was conducted over a five-year span of patients undergoing fusions in the foot and ankle where the cellular allograft was used. We compared the ROF and TTF between the following three graft groups: cellular allograft alone, autograft alone, and combined allograft + autograft. Data was retrieved from the patients' electronic medical record and TTF was recorded as the time, in days, it took for a solid radiographic fusion to form. Secondary variables collected included etiology of disease (post-traumatic, inflammatory, or diabetic arthropathy) and also analyzed for effect on ROF and TTF.
Results:
Two hundred and twenty-five patients underwent a fusion in the foot or ankle over a five-year period. Autograft alone was used in 101 patients, the cellular allograft alone was used in 88 patients, and a combination of autograft and the cellular allograft was used in 36 patients. Each group were similar in their comorbid conditions and demographics. The ROF of the autograft only group was 88% (89/101), compared to the cellular allograft group's ROF of 89% (78/88), and the combination graft group's ROF of 75% (27/36). The average TTF between each group varied slightly, with the cellular allograft group fusing the fastest at 86, followed by the autograft alone group at 97 days, and the combined group at 112 days.
Conclusion:
Our study investigated the use of a viable cellular allograft and its effect on ROF and TTF compared to autograft alone and autograft combined with said cellular allograft. We found no significant difference in ROF between autograft alone and the cellular allograft alone but did find a significant difference in ROF for the combined group resulting in lower rate of fusion. Additionally, use of the cellular allograft resulted in fastest time to fusion compared to autograft alone or a combination of the graft types.
Category:
Ankle; Trauma
Introduction/Purpose:
Ankle fractures are the most common fractures of the lower extremity. In spite of that, there is still no consensus regarding the best way to approach ...posterior malleolus (PM) fractures. The aim of this study is to compare the degree of PM exposure, tension of the flap containing the medial neurovascular bundle (NVB) and distance between the surgical incision and the NVB using three different posteromedial ankle approaches.
Methods:
Three different posteromedial approaches were compared: direct medial (DM) modified posteromedial (MPM) and posterior paramedian (PPM). Each approach was performed four times using a standardized technique. With a digital tensiometer, the minimal tension of the flap containing the NVB that allowed proper exposure of the PM was measured. In a second stage, an axial cut 1cm proximal to the tibiotalar joint was performed in nine frozen pieces and PM exposure degree and distance between the incision and the NVB was measured.
Results:
The median minimal tension was DM: 14,78 N, MPM: 8N and PPM: 5,75N. The median distance between the incision and the NVB was DM: 17mm, MPM: 6mm and PPM: 28mm. The median degree of exposure was DM: 51%, MPM: 58% and PPM: 72%.
Conclusion:
The PPM approach achieved the highest degree of PM exposure, with the lowest tension applied to the NVB and allowing the greatest distance between the incision and the NBV. Thus, we believe it should be considered the approach of choice for large fractures compromising the posteromedial and posterolateral aspect of the PM.
Category:
Ankle
Introduction/Purpose:
The sural nerve (SN) is a distal cutaneous nerve that provides sensation to the lateral foot and ankle, and is at risk of iatrogenic injury during surgery at the ...foot and ankle.1 Previous anatomic studies of the SN are limited to cadaveric studies with small sample sizes.2,3,4,5,6,7,8,9 We analyzed a large cohort of high-field 3 Tesla (3T) magnetic resonance images (MRI) of the ankle to obtain a more generalizable, in-vivo sample of the distal course of the SN. A comparison of this in- vivo method of measurement vs. cadaveric studies may provide surgeons with a more accurate representation of SN anatomy and its relation to anatomic landmarks.
Methods:
We performed a retrospective review of 3T MRI studies of the ankle performed at our institution between January 2015 and December 2020. Three blinded reviewers measured the vertical distance of the SN to the distal tip of the lateral malleolus (DTLM), the horizontal distance of the SN to the DTLM, and the lateral border of the Achilles tendon (LBA) at the level of the DTLM. Also measured was the horizontal distance of the SN to the LBA at the level of superior Achilles insertion (SAI) onto the calcaneus as well, as 5 cm above the SAI. Intraclass correlation coefficient was calculated to assess reliability between reviewers. A total of 204 3T MRIs of the ankle were included.
Results:
The mean vertical distance from the SN to the DTLM was 2.2 +- 0.5 cm (ICC, 0.85; range 0.9-3.6 cm). The mean horizontal distance of the SN to the DTLM at the level of DTLM was 1.7 +- 0.3 cm (ICC, 0.98; range 0.8-3.0 cm). The mean horizontal distance of the SN to the LBA at the level of DTLM was 1.9 cm +- 0.3 cm (ICC, 0.91; range 1.0-2.9 cm). The mean horizontal distance from the SN to the LBA at the level of the SAI and 5 cm above the SAI was 2.6 +- 0.4 cm (ICC, 0.85; range 1.4-3.7 cm) and 0.9 +- 0.2 cm (ICC, 0.87; range 0.4-1.8 cm), respectively. Neither height nor BMI were strongly associated with the distance of the SN to any of our anatomic landmarks (R2 < 0.08 for all measurements).
Conclusion:
Several of our measurements summarized in differed from those reported in previous cadaveric studies. Although our mean horizontal distance of SN to LBA at SAI differed notably from cadaveric studies (2.6 cm vs 1.8-2.1 cm), a 2018 ultrasound study of the SN by Popieluszko et al observed a mean distance of 2.4 cm for this measurement. This concordance may indicate reliability between in-vivo methods of measurement vs. cadaveric studies. In-vivo measurements may also provide a more accurate representation of the anatomy, as these methods are not subject to the effects of embalming and dissection required of cadaveric studies.
Category:
Ankle
Introduction/Purpose:
The traditional modified Brostrom-Gould has long been the procedure of choice for addressing chronic lateral ankle instability. However, more robust techniques ...including anatomic reconstruction are favored for larger deformity, poor tissue quality and revision surgery. Given the inherent disadvantages of allograft and non-elastic synthetic materials, material science has sought to impact the graft choice providing alternative load sharing, permeable materials with high strength. Our institution has performed anatomic lateral ligament stabilization, termed the 'ATLAS' procedure, using a novel synthetic graft (Artelon, Marietta, GA) with anecdotal success in recent years. In this study, we present our surgical technique and early experience.
Methods:
A retrospective cohort review was performed, evaluating the failure rate, complications and radiographic changes in anatomic alignment. A review of all patients undergoing the ATLAS procedure was performed, a total of 27 patients were included. The study included only those patients with at least 1 year follow up from the procedure.
Results:
Only one patient had symptoms of early failure of the procedure, while none of the patients required a revision procedure. The most common complication was minor wound dehiscence (11.1%). Overall, our short-term results with this procedure were excellent.
Conclusion:
We conclude that the ATLAS procedure is a predictable and effective lateral ligament reconstruction technique with no donor site morbidity, no donor tissue transmission risk, low risk of over-constraint and accomplished with a predictable technique.
Category:
Ankle; Trauma
Introduction/Purpose:
The use of intraoperative three-dimensional fluoroscopy to evaluate syndesmotic and articular reduction in ankle fractures is a relatively new tool ...demonstrating usefulness in the literature. It has been described that it can detect up to 32.7% of intraoperative malreduction. The objective of this prospective study is to observe if surgeons, when performing operative treatment in ankle fractures with three- dimensional fluoroscopy assistance, modify the syndesmotic reduction and/or fixation. The definitive syndesmotic reduction was assessed with bilateral ankle CT-scan postoperatively.
Methods:
Sixteen patients with ankle fracture and syndesmotic instability were analyzed. After malleolar and syndesmotic fixation, intraoperative three-dimensional fluoroscopy was performed. The surgeon then analyzed cross-sectional images to evaluate the reduction of the fracture and syndesmosis. In this scenario, the surgeon decided whether to make any changes in the reduction of the syndesmosis or in the configuration of the fixation strategy. Postoperative bilateral computed tomography was carried out to corroborate in detail if there was any syndesmotic malreduction.
Results:
Sixteen patients were included in this study (10 men) with a mean age of 40 years (range 25-60 years). 62% were supination-external rotation fractures according to Lauge-Hansen classification. Of all the patients evaluated, only 4 underwent any modification after performing intraoperative three-dimensional fluoroscopy. From the previous group, in 3 patients (19% of the total) there was a change in syndesmal reduction and in only one there was a change of any element of osteosynthesis. When evaluating syndesmal reduction with postoperative bilateral CT, there were 6 patients in the total group who presented syndesmal malreduction. In patients in whom a modification to syndesmal reduction was made, it persisted in 2 of the 3 cases.
Conclusion:
In our series, the use of intraoperative three-dimensional fluoroscopy did not motivate most surgeons to make changes in syndesmotic reduction, unlike other previously published studies. Even despite making changes in syndesmotic reduction, the percentage of patients who persists with poor reduction is considerable. In this study, the percentage of poor syndesmotic reductions was 32.7%. Despite being a figure that is within what is expected according to the literature, we consider that it is high even using intraoperative fluoroscopy as support.
Background:
Ankle arthrodesis has historically been the standard of care for end-stage ankle arthritis; however, total ankle arthroplasty (TAA) is considered a reliable alternative. Our objective was ...to compare 3-dimensional foot and ankle kinetics and kinematics and determine the ankle power that is generated during level walking and stair ascent between TAA and ankle arthrodesis patients.
Methods:
Ten patients who underwent TAA with a modern fixed-bearing ankle prosthesis and 10 patients who previously underwent ankle arthrodesis were recruited. Patients were matched for age, sex, body mass index, time from surgery, and preoperative diagnosis. A minimum of 2-year follow-up was required. Patients completed instrumented 3D motion analysis while walking over level ground and during stair ascent. Between-group differences were assessed with a 2-tailed Mann-Whitney exact test for 2 independent samples.
Results:
Sagittal ankle range of motion (ROM) was significantly higher in the TAA group (21.1 vs 14.7 degrees, P = .003) during level walking. In addition, forefoot-tibia motion (25.3±5.9 degrees vs 18.6±5.1 degrees, P = .015) and hindfoot-tibia motion (15.4±3.2 degrees vs 12.2±2.5 degrees, P = .022) were significantly greater in the TAA group. During stair ascent, sagittal ankle ROM (25 vs 17.1 degrees, P = .026), forefoot-tibia motion (27.6 vs 19.6 degrees, P = .017), and hindfoot-tibia motion (16.8 vs 12 degrees, P = .012) was greater.
Conclusion:
There were significant differences during level walking and stair ascent between patients with TAA and ankle arthrodesis. TAA patients generated greater peak plantarflexion power and sagittal motion within the foot and ankle compared to patients with an ankle arthrodesis. Further investigation should continue to assess biomechanical differences in the foot and ankle during additional activities of daily living.
Level of Evidence:
Level III, comparative study.
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