Clinical Relevance of Hindfoot Alignment View in Total Ankle Replacement

2010 ◽  
Vol 31 (10) ◽  
pp. 871-879 ◽  
Author(s):  
Arno Frigg ◽  
Benno Nigg ◽  
Laura Hinz ◽  
Victor Valderrabano ◽  
Iain Russell
Keyword(s):  
Clinical Relevance ◽  
Total Ankle Replacement ◽  
Hindfoot Alignment ◽  
Ankle Replacement

scholarly journals 2019 IFFAS Award for Excellence Winner: Peri-Prosthetic Cysts and Alignment in Total Ankle Replacement: A 3-D, Weight Bearing Topographical Study

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0004
Author(s):  
Francois Lintz ◽  
Jef Mast ◽  
Nazim Mehdi ◽  
Alessio Bernasconi ◽  
Cesar de Cesar Netto ◽  
...  
Keyword(s):  
Weight Bearing ◽  
Total Ankle Replacement ◽  
Coronal Plane ◽  
Unequal Distribution ◽  
Hindfoot Alignment ◽  
Cyst Volume ◽  
Ankle Replacement ◽  
The Mean ◽  
The Difference

Category: Ankle, Ankle Arthritis Introduction/Purpose: Peri-prosthetic cysts (PPC) in Total Ankle Replacement (TAR) are a common failure cause but the mechanisms of their development remains unclear. One possible explanation could be hindfoot malalignment and subsequent unequal distribution of load inside the joint. However, how residual malalignment influences the evolution of PPC remains unclear. Computed tomography (CT) has demonstrated superiority on conventional radiography in the follow up of PPC. Weight Bearing CT (WBCT), by combining 3D imaging and weight bearing measurements seems a valid tool to investigate this further. The objective for this work was to study the effects of residual hindfoot deformity on the distribution of PPC in the coronal plane. We hypothesized that cysts would be found predominantly medially in varus configuration, and laterally in valgus configuration. Methods: Retrospective comparative study, ethics committee approved. Forty-eight cases of TAR were included, with relevant demographics. Inclusion criteria were cases of primary TAR with available WBCT imaging of their ankle as part of normal follow up. Exclusion criteria were subsequent implant revision or cyst grafting. In each case, the localization and size of PPC’s were documented and their volume calculated by approximation of the closest ellipsoid. Hindfoot alignment was evaluated by the percentage Foot Ankle Offset (FAO) (foot-length normalized 3D ratio between the midline of the foot and the center of the ankle) using a WBCT dedicated semi-automatic software. The mean FAO value with 95%CI for the population was calculated. The difference in medial and lateral cyst volume defined by their position relative to the median axis in the coronal plane was compared in varus and valgus cases by a Mann-Whitney non-parametric test for unpaired samples. Results: Demographic distributions of the series were 32% female, mean age 65 (45-85) years. Mean FAO value was 0.12% (95%CI -1.09 to 1.33). Mean follow up was 43 months (6 to 239). The mean total cyst volume per case was 1190,7 mm3. In varus cases (defined by FAO<-1.09%), the volume of medial cysts was greater than laterally by a mean 197 mm3, whereas in valgus cases (defined by FAO>1.33%), the volume of lateral cysts was greater than medially by a mean 332 mm3. The difference was statistically significant (p<0.05). There was a weak, significant positive correlation (r=0.25, p<0,001) between FAO and total cyst volume and a moderate, significant correlation (r=0,56, p<0,001) between time to follow up and total cyst volume. Conclusion: Our hypothesis was confirmed. Periprosthetic cysts volume in this series of primary TAR was found to be relatively greater medially in postoperative varus configurations and vice-versa laterally in valgus. This confirms a possible correlation between the direction of residual hindfoot malalignment and the coronal localization of PPC in TAR, although this is certainly not the only pathophysiologic factor involved in PPC onset. Weightbearing CT may be helpful in Total Ankle Replacement follow up, in order to early detect PPC development and possibly to identify situations at risk of a more rapid evolution.

scholarly journals Syndesmotic Instability After Total Ankle Replacement

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0010
Author(s):  
Roxa Ruiz ◽  
Lukas Zwicky ◽  
Beat Hintermann
Keyword(s):  
Ankle Joint ◽  
Tibial Component ◽  
External Rotation ◽  
Articular Surface ◽  
Cyst Formation ◽  
Total Ankle Replacement ◽  
Hindfoot Alignment ◽  
Additional Degree ◽  
Component Design ◽  
Ankle Replacement

Category: Ankle Arthritis Introduction/Purpose: Total ankle replacement (TAR) evolved over the last decades and has been shown to be an effective concept in the treatment of ankle osteoarthritis (OA). In three-component designs, the second interface between polyethylene insert (PI) and tibial component allows the PI to find its position according the individual physiological properties. This was believed to decrease shear forces within the ankle joint. However, it is not clarified to which extent such an additional degree of freedom may overload the ligamentous structures of the ankle joint over time. This may in particular be the case for the syndesmotic ligaments. Therefore, the purpose of this study was to analyze all ankles after TAR that showed a symptomatic overload of the syndesmotic ligaments and to determine the potential consequences. Methods: Between 2003 and 2017, 31 ankles (females, 17; males 14; mean age 60 [40-79] years) were treated with a tibio-fibular fusion for a symptomatic instability of the syndesmosis. The indication for TAR was posttraumatic OA in 27 (87%), primary OA in 3 (10%), and hemochromatosis in one ankle (3%). The 31 ankles included 23 primary TAR (74%), 6 revision TAR (19%), and two take-down of a fusion and conversion to TAR (7%). Criteria for fusion were the presence of at least two of the followings: (1) tenderness over the syndesmosis, (2) pain while compressing the fibula against the tibia (squeeze test), (3) pain while rotating the foot externally (external rotation test), (4) widening of the syndesmosis on an anteroposterior view. Alignment of TAR (tibial articular surface [TAS] angle) and hindfoot alignment were measured on standard radiographs. Intraoperatively, the syndesmotic instability was confirmed before fusion. The wear of PI was documented. Results: After a mean of 63 (range, 4 – 152) months after TAR, all patients evidenced pain at the level of the syndesmosis of at least 3 months. 25 ankles (81%; 24 after posttraumatic OA) showed a widening of the syndesmotic space and 22 ankles (71%) of the medial clear space with lateral translation of the talus. The PI was seen to overlap the tibial component in 15 ankles (48%). Nine ankles (29%) evidenced cyst formation, and eight ankles (26%) showed a decrease in height of the PI; whereas, in 3 ankles (10%) a fracture of the PI was found. A valgus misalignment of the heel was found in 25 ankles (81%), a valgus TAS in 16 (52%) and a varus TAS in 11 ankles (36%). Conclusion: A syndesmotic instability after a three-component TAR apparently occurred mostly after posttraumatic OA, in particular if the heel was left in valgus. If the talus starts to move lateralward, the PI seems to be at risk for increased wear and finally mechanical failure (Figure 1). Therefore, a valgus misaligned heel should always be corrected during TAR implantation. If there is any sign of syndesmotic instability, a fusion should be considered. Further studies must proof whether in cases with a syndesmotic instability the use of a two-component design will be superior, as it stabilizes the talus in the coronal plane.

scholarly journals Clinical and Radiological Outcomes of Transfibular Total Ankle Arthroplasty at 2-years Follow-up

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0005
Author(s):  
Francesco Granata ◽  
Camilla Maccario ◽  
Luigi Manzi ◽  
Eric Tan ◽  
Federico Giuseppe Usuelli
Keyword(s):  
Functional Limitation ◽  
Total Ankle Replacement ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthritis ◽  
Hindfoot Alignment ◽  
Ankle Arthroplasty ◽  
Ankle Replacement ◽  
Patient Reported ◽  
American Orthopaedic

Category: Ankle Arthritis Introduction/Purpose: Ankle arthritis is a highly limiting pathology that causes pain and functional limitation with subsequent deterioration of quality of life. With recent advances in surgical instrumentation and techniques, prosthetic replacement of the ankle has proved to be a valid alternative to arthrodesis with comparable outcomes. The purpose of this study was to evaluate clinical and radiological findings in a transfibular total ankle replacement with two years follow-up. Methods: This prospective study included 59 patients who underwent transfibular total ankle arthroplasty from May 2013 to December 2015. The mean age was 51.6 ± 13.4 years. All patients were followed for at least 24 months postoperative with an average follow-up of 42.0 ± 23.5 months. Patients were assessed clinically and radiologically preoperatively and at 6, 12, and 24 months postoperatively. Results: At 24 months, patients demonstrated statistically significant improvement in the American Orthopaedic Foot and Ankle Society score from 33.6 to 88.1 (P<0.01), VAS scale from 79.3 to 14.0 (P<0.01) and SF-12 Physical and Mental Composite Scores from 29.9 and 44.6 to 74.4 and 95.3, respectively (P<0.01). Ankle dorsiflexion and plantarflexion improved from 5.5 and 8.8 degrees to 24.2 and 20.0 degrees, respectively (P<0.01). Radiographically, patients demonstrated neutral alignment of the ankle with a tibio-talar ratio of 34.9 ± 9.2 and hindfoot alignment view angle of 1.2 ± 7.0 degrees. No patient demonstrated any radiographic evidence of tibial or talar lucency at 24 months. Seven patients underwent reoperation for removal of symptomatic hardware; one patient developed a postoperative prosthetic infection requiring placement of an antibiotic spacer. Conclusion: This study demonstrates that transfibular total ankle replacement is a safe and effective option for the patients for ankle arthritis with improvements in patient-reported outcomes, range of motion, and radiological parameters. However, further studies are required to determine the mid- and long-term performance of these implants.

scholarly journals Hindfoot Alignment after Total Ankle Replacement

2020 ◽  
Vol 5 (2) ◽  
pp. 2473011420S0000
Author(s):  
Christopher E. Gross ◽  
Federico Guiseppe Usuelli ◽  
Christian Indino
Keyword(s):  
Sagittal Alignment ◽  
Mobile Bearing ◽  
Total Ankle Replacement ◽  
Fixed Bearing ◽  
Ankle Arthritis ◽  
Hindfoot Alignment ◽  
Time Points ◽  
Ankle Replacement ◽  
Temporal Course ◽  
Over Time

Category: Ankle Arthritis; Ankle Introduction/Purpose: End-stage ankle arthritis can involve misalignment of the ankle in both the coronal and sagittal planes as up to reported 33% to 44% of patients who present for total ankle replacement have greater than 10° of coronal plane deformity. Improvements in both the design and surgical technique for total ankle replacements (TAR) have allowed surgeons to tackle the most challenging of multiplanar ankle deformities. Normalization of the sagittal and coronal alignment is key in improving survivorship and functional outcomes in TAR. In the present study, we analyzed how both the ankle and hindfoot alignment for both a fixed-bearing and mobile bearing TAR system changes over time. Specifically, we measured coronal and sagittal alignment of both the ankle and hindfoot complex. We hypothesize that both significant differences would be seen between all time points and pre-operative radiographs, and that these differences would not change over time. Methods: A retrospective study performed by a single orthopaedic surgeon was performed on two independent groups of patients undergoing two different systems for total ankle replacement: Zimmer TAR (lateral-approach, fixed-bearing, n=89) and Hintegra (anterior approach, mobile-bearing, n=81). We noted specific demographic data and radiographic data were measured including: Hindfoot alignment view angle (HAV), Hindfoot alignment distance (HAVD), tibiotalar ratio, α angle and β angle. These were measured pre-operatively, and 6 months, 12 months, and 24 months post-operatively. Within-group comparisons were performed using one-way repeated-measures ANOVA (1-w rANOVA), analyzing temporal course of clinical data (comparisons between different time points, e.g. T0vsT6vsT12vsT24) within the Hintegra and Zimmer groups. To compare the time course of clinical measures between the two groups, 2-w rANOVAs were performed for SA, SD, TT ratio, α and β angle. Specifically, time*group interaction was tested. Results: At the ankle joint itself, as measured by the α and β angles (p>.05), the position of the components remains relatively similar in both the fixed and mobile bearing TAR over the course of 24 months. The sagittal alignment, as measured by the TT ratio, demonstrated a posterior shifting of the talus in the mobile bearing group (p=.036). Though the fixed and mobile- bearing TAR had both significant hindfoot alignment improvement between the pre-op radiographs and twenty-four months, over time, the fixed-bearing ankle had a significant increase in both the HAV and HAVD (p<.001), suggesting a dynamism of the hindfoot in the fixed-bearing ankle. Conclusion: Correcting coronal and sagittal alignment is important for the long-term survivorship of a TAR. The fixed and mobile-bearing implants had maintained coronal and sagittal alignment in the short term, the temporal course of the fixed-bearing ankle showed an increased in the valgus positioning of the hindfoot.

scholarly journals Hindfoot Alignment after Total Ankle Replacement

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0018
Author(s):  
Christopher Gross ◽  
Luigi Manzi ◽  
Cristian Indino ◽  
Fausto Romano ◽  
Camilla Maccario ◽  
...  
Keyword(s):  
Sagittal Alignment ◽  
Mobile Bearing ◽  
Total Ankle Replacement ◽  
Fixed Bearing ◽  
Ankle Arthritis ◽  
Hindfoot Alignment ◽  
Time Points ◽  
Ankle Replacement ◽  
Temporal Course ◽  
Over Time

Category: Ankle, Ankle Arthritis Introduction/Purpose: End-stage ankle arthritis can involve misalignment of the ankle in both the coronal and sagittal planes as up to reported 33% to 44% of patients who present for total ankle replacement have greater than 10° of coronal plane deformity. Normalization of the sagittal and coronal alignment is key in improving survivorship and functional outcomes in TAR. In the present study, we analyzed how both the ankle and hindfoot alignment for both a fixed-bearing and mobile bearing TAR system changes over time. Specifically, we measured coronal and sagittal alignment of both the ankle and hindfoot complex. We hypothesize that both significant differences would be seen between all time points and pre-operative radiographs, and that these differences would not change over time. Methods: A retrospective study performed by a single orthopaedic surgeon was performed on two independent groups of patients undergoing two different systems for total ankle replacement: Zimmer TAR (lateral-approach, fixed-bearing, n=89) and Hintegra (anterior approach, mobile-bearing, n=81). We noted specific demographic data and radiographic data were measured including: Hindfoot alignment view angle (HAV), Hindfoot alignment distance (HAVD), tibiotalar ratio, a angle and ß angle. These were measured pre-operatively, and 6 months, 12 months, and 24 months post-operatively. Within-group comparisons were performed using one-way repeated-measures ANOVA (1-w rANOVA), analyzing temporal course of clinical data (comparisons between different time points, e.g. T0vsT6vsT12vsT24) within the Hintegra and Zimmer groups. To compare the time course of clinical measures between the two groups, 2-w rANOVAs were performed for SA, SD, TT ratio, a and ß angle. Specifically, time*group interaction was tested. Results: At the ankle joint itself, as measured by the a and ß angles (p>.05), the position of the components remains relatively similar in both the fixed and mobile bearing TAR over the course of 24 months. The sagittal alignment, as measured by the TT ratio, demonstrated a posterior shifting of the talus in the mobile bearing group (p=.036). Though the fixed and mobile-bearing TARhad both significant hindfoot alignment improvement between the pre-op radiographs and twenty-four months, over time, the fixed-bearing ankle had a significant increase in both the HAV and HAVD (p<.001), suggesting a dynamism of the hindfoot in the fixed-bearing ankle. Conclusion: Correcting coronal and sagittal alignment is important for the long-term survivorship of a TAR. The fixed and mobile-bearing implants had maintained coronal and sagittal alignment in the short term, the temporal course of the fixed-bearing ankle showed an increased in the valgus positioning of the hindfoot. The mobile-bearing implant maintained its hindfoot alignment over the course of the study. More studies are needed to explore the clinical implications of this new data.

Evaluation of Hindfoot Alignment After Fixed- and Mobile-Bearing Total Ankle Prostheses

2019 ◽  
Vol 41 (3) ◽  
pp. 286-293
Author(s):  
Federico G. Usuelli ◽  
Camilla Maccario ◽  
Cristian Indino ◽  
Luigi Manzi ◽  
Fausto Romano ◽  
...  
Keyword(s):  
Anterior Approach ◽  
Sagittal Alignment ◽  
Mobile Bearing ◽  
Lateral Approach ◽  
Total Ankle Replacement ◽  
Fixed Bearing ◽  
Hindfoot Alignment ◽  
Ankle Replacement ◽  
Temporal Course ◽  
Over Time

Background: End-stage ankle arthritis can involve malalignment of the ankle in both the coronal and sagittal planes. Up to 33% to 44% of patients who present for total ankle replacement (TAR) have greater than 10° of coronal plane deformity. Normalization of the sagittal and coronal alignment is key in improving survivorship and functional outcomes in TAR. In the present study, we analyzed how both the ankle and hindfoot alignment for both a fixed-bearing and mobile-bearing TAR system changed over time. Specifically, we measured coronal and sagittal alignment of both the ankle and hindfoot complex. Methods: A retrospective study was performed on 2 independent groups of patients undergoing 2 different systems for total ankle replacement: Zimmer (lateral approach, fixed-bearing) and Hintegra (anterior approach, mobile bearing). Specific demographic data and radiographic data were measured. Within-group comparisons were performed using 1-way repeated measures ANOVA, analyzing the temporal course of clinical data within the Hintegra and Zimmer groups. Results: At the ankle joint, as measured by the α and β angles ( P > .05), the position of the components remained relatively similar in both the fixed- and mobile-bearing TAR at 24-month follow-up. The sagittal alignment, as measured by the TT (tibiotalar) ratio, demonstrated a posterior shifting of the talus in the mobile bearing group ( P = .036). Although the fixed- and mobile-bearing TAR had both significant hindfoot alignment improvement between the preoperative radiographs and at 24 months, over time, the fixed-bearing ankle had a significant increase in both the hindfoot alignment view angle and hindfoot alignment distance ( P < .001), suggesting a possible dynamism of the hindfoot in the fixed-bearing TAR. Conclusion: The lateral-approach fixed and anterior approach mobile-bearing implants maintained coronal and sagittal alignment in the short term; the temporal course of the lateral approach fixed-bearing ankle showed an increase in the valgus positioning of the hindfoot. The anterior approach mobile-bearing implant maintained its hindfoot alignment over the course of the study. Level of Evidence: Level III, case-control study.

scholarly journals Ankle Range of Motion after Total Ankle Replacement with and without Heel Cord Lengthening

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0036
Author(s):  
Roxa Ruiz ◽  
Nicola Krähenbühl ◽  
Alexej Barg ◽  
Beat Hintermann
Keyword(s):  
Correlation Analysis ◽  
Range Of Motion ◽  
Pearson Correlation ◽  
Weight Bearing ◽  
Total Ankle Replacement ◽  
Hindfoot Alignment ◽  
Ankle Replacement ◽  
Pearson Correlation Analysis ◽  
End Stage ◽  
Limited Motion

Category: Ankle, Ankle Arthritis Introduction/Purpose: Though total ankle replacement (TAR) has become a well-accepted alternative to fusion for treatment of end-stage ankle osteoarthritis (OA), controversy still exists regarding the appropriate indications. In 80% of the cases, trauma accounts for the primary cause of end-stage ankle OA. In these cases, the soft tissue conditions are often poor and the remaining ankle range of motion (ROM) limited. Additionally, performing a heel cord lengthening (HCL) should theoretically increase ankle ROM. However, it remains unclear to which extent a preoperative stiff ankle can become mobile after a TAR, with or without a HCL. The purpose of this study was to assess the gained ROM after TAR in end-stage ankle OA, and whether it is beneficial for patients who additionally underwent a HCL. Methods: Out of 605 primary TAR performed at our institution between 2006 and 2015, 288 ankles (280 patients; age 64.1 [39 – 88]; male, 151; female, 129) were identified with a neutral hindfoot alignment, no degenerative changes or previous fusions of adjacent joints, and no previous ligament reconstruction and tendon transfers at time of TAR. Medial and lateral gutter debridement as well as a complete posterior capsule resection was performed before the prosthesis was inserted. The ankle was then gradually mobilized into dorsiflexion. If a minimum of 10° dorsiflexion could not be obtained, HCL was performed (percutaneous triple hemisection). Postoperatively, the ankle was protected by a walker and weight-bearing was permitted as tolerated. ROM was determined during weight-bearing with the use of a goniometer preoperatively and 2-years postoperatively. Pearson correlation analysis and paired t-test were used for statistical analysis. Results: Out of 288 ankles, 41 (14.2%) underwent additional HCL. Preoperative ROM correlated with the ROM 2-years after TAR, independent whether a HCL was performed (p < 0.01) or not (p < 0.01). ROM for the ankles where no HCL was performed was 35° preoperatively and 34° 2-years postoperatively. For the ankles in which a HCL was performed, it was 28° preoperatively and 28° 2-years postoperatively. Pearson correlation analysis showed that patients with a low ROM preoperatively tended to get more motion after TAR, whereas patients with an extensive preoperative ROM even lost some motion after receiving a TAR system (Figure 1). Conclusion: The data suggests that a HCL procedure has little potential to ameliorate a preoperative low ROM. A TAR system however, may help increase the ROM in patients with little preoperative ROM while in patients with extensive preoperative ROM it may even cause a loss of ROM. The data further suggests that the heel cord contracture is not the only cause of limited motion in end-stage ankle OA, and that whether TAR nor TAR in combination with HCL should be performed with the goal of gaining ROM for the treatment of end-stage OA.

scholarly journals The Use of Three-Dimensional (3D) Biometric Measurements to Predict Additional Alignment Procedures in Total Ankle Replacement

2019 ◽  
Vol 4 (2) ◽  
pp. 2473011419S0000
Author(s):  
Cesar de Cesar Netto ◽  
Lauren Roberts ◽  
Ashraf Fansa ◽  
Meghan Newcomer ◽  
Guilherme Saito ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Surgical Planning ◽  
Three Dimensional ◽  
Preoperative Assessment ◽  
Total Ankle Replacement ◽  
Foot And Ankle ◽  
Varus Alignment ◽  
Hindfoot Alignment ◽  
Ankle Replacement ◽  
The Mean

Category: Ankle Arthritis Introduction/Purpose: Preoperative evaluation of ankle and hindfoot deformities in patients undergoing total ankle replacement (TAR) is challenging. Characterizing deformity based on conventional radiographs is limited by its two-dimensional (2D) nature and is influenced by anatomical and operator-related bias. The final decision to perform associated corrective alignment procedures, that include calcaneal osteotomies, midfoot and forefoot osteotomies/fusions, and soft tissue balancing, is made intraoperatively following insertion of the TAR components. The use of weightbearing cone beam CT (WB CBCT) images and three-dimensional (3D) biometric tools, encompassing the hindfoot alignment, foot tripod, and center of the ankle joint, may be an effective surgical planning instrument. In this retrospective study, we assessed the ability of these tools to predict additional procedures performed at the time of TAR. Methods: In this retrospective study, we enrolled 22 patients that underwent TAR and had preoperative WB CBCT studies. We excluded seven patients with isolated ankle CBCT images and three with metallic hindfoot implants. Patients demographics, type and number of additional alignment procedures were noted. The WB CBCT data sets were screened using built-in semi-automatic measurement software. 3D coordinates (x/y/z) were identified for the specific anatomical landmarks required to calculate Foot and Ankle Offset (FAO), which included the WB points of the first, fifth metatarsal heads and calcaneus, as well as the highest point of the talar dome. FAO is a representation of the torque (offset) between the hindfoot/forefoot midline and the center of the talus, and is given as a percentage of foot-length. Patients were then divided into varus and valgus hindfoot alignment groups accordingly to their measured FAO, using available literature FAO values for normally aligned feet (2.3%, ±2.9%). Results: We included 12 patients (6F/6 M), mean age 65 (range, 47-80). The mean preoperative FAO was 5.73 (CI -0.99 - 12.55). Seven patients had valgus and 5 patients had varus alignment of the hindfoot. The mean number of additional procedures was 2 (range, 0 to 5), and included: calcaneal osteotomy (58%), Achilles lengthening/Gastroc recession (58%), Cotton osteotomy (25%), First TMT fusion (17%), talonavicular fusion, naviculo-cuneiform fusion, and Brostrom procedure (8%). The FAO positively correlated with occurrence of additional alignment procedures (p=0.003). Patients with valgus hindfoot alignment had significantly increased number of additional procedures (2.7; CI 1.6 – 3.8) when compared to varus alignment patients (1.2; CI -0.1 – 2.5) (p=0.03), and were found to have a 1.8 fold greater chance to have a calcaneal osteotomy. Conclusion: This is the first study to evaluate the role of 3D biometric tools and semi-automatic WB CBCT measurements in the preoperative assessment of foot alignment in patients undergoing TAR. We found that increased Foot and Ankle Offset (FAO) significantly predicts the occurrence and number of additional alignment procedures, including calcaneal osteotomies. We believe that the use of biometrics and semi-automatic measurements, which account for the relationship between the center of the ankle and the tripod of the foot, can enhance the preoperative assessment, surgical planning and outcomes of TAR patients. Prospective and postoperative studies demonstrating correction are needed.

3D, Weightbearing Topographical Study of Periprosthetic Cysts and Alignment in Total Ankle Replacement

2019 ◽  
Vol 41 (1) ◽  
pp. 1-9 ◽  
Author(s):  
François Lintz ◽  
Jef Mast ◽  
Alessio Bernasconi ◽  
Nazim Mehdi ◽  
Cesar de Cesar Netto ◽  
...  
Keyword(s):  
Roc Curves ◽  
Threshold Value ◽  
Total Ankle Replacement ◽  
Level Of Evidence ◽  
Hindfoot Alignment ◽  
Ankle Replacement ◽  
Increased Risk ◽  
The Mean ◽  
American Orthopaedic

Background: We investigated the association between hindfoot residual malalignment assessed on weightbearing computed tomography (WBCT) images and the development of periprosthetic cysts (PPCs) after total ankle replacement (TAR). We hypothesized that PPCs would be found predominantly medially in the varus configuration and laterally in the valgus configuration. Methods: Cases of primary TAR with available WBCT imaging of the ankle were included in this retrospective study. The location of the PPC was marked and the following volumes were calculated: total (TCV), medial (MCV), central (CCV), and lateral (LCV) cyst volumes. Hindfoot alignment was measured as Foot and Ankle Offset (FAO), with 95% confidence intervals (95% CIs) calculated to define varus (<95% CI) and valgus (>95% CI) groups. Cyst volumes were compared between these 2 groups. The American Orthopaedic Foot & Ankle Society (AOFAS) score at the time of the WBCT was also retrieved. Receiver operating characteristic (ROC) curves were used to determine FAO thresholds for predicting an increased risk of PPC. Results: Forty-eight TARs (mean follow-up, 44.6 months) were included, 81% of which had at least 1 PPC. The mean FAO was 0.12% (95% CI, –1.12 to 1.36). Patients with greater residual malalignment ( P < .001) and those with longer follow-up ( P < .001) presented with increased TCV. In varus cases, the MCV was greater than the LCV ( P = .042), with a threshold FAO value of −2.75% or less predicting an increased MCV. In valgus cases, the LCV was greater than the MCV ( P = .049), with a FAO threshold value of 4.5% or more predicting an increased LCV. Conclusion: In this series, the PPC volume after primary TAR significantly correlated with postoperative hindfoot malalignment and longer follow-up. Level of Evidence: Level III, retrospective comparative series.

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