scholarly journals Hindfoot Alignment after Total Ankle Replacement

2020 ◽  
Vol 5 (2) ◽  
pp. 2473011420S0000
Author(s):  
Christopher E. Gross ◽  
Federico Guiseppe Usuelli ◽  
Christian Indino

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.

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0018
Author(s):  
Christopher Gross ◽  
Luigi Manzi ◽  
Cristian Indino ◽  
Fausto Romano ◽  
Camilla Maccario ◽  
...  

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.


2019 ◽  
Vol 41 (3) ◽  
pp. 286-293
Author(s):  
Federico G. Usuelli ◽  
Camilla Maccario ◽  
Cristian Indino ◽  
Luigi Manzi ◽  
Fausto Romano ◽  
...  

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.


2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0009
Author(s):  
James Nunley ◽  
Samuel Adams ◽  
James DeOrio ◽  
Mark Easley

Category: Ankle Arthritis Introduction/Purpose: Outcomes of total ankle replacement for the treatment of end-stage ankle arthritis continue to improve. Debate continues whether a mobile-bearing total ankle replacement (MB-TAR) or a fixed-bearing total ankle replacement (FB-TAR) is superior, with successful outcomes reported longterm for MB-TAR and at intermediate-to-longterm follow-up for newer generation FB-TAR. Although comparisons between the two total ankle designs have been reported, to our knowledge, no investigation has compared the two designs with a high level of evidence. This prospective, randomized controlled trial conducted at a single institution compares patient satisfaction, functional outcomes and radiographic results of the mobile-bearing STAR and the fixed-bearing Salto-Talaris in the treatment of end-stage ankle arthritis. Methods: This investigation was approved by our institution’s IRB committee. Between November 2011 and November 2014, adult patients with end-stage ankle osteoarthritis failing nonoperative treatment were introduced to the study. With informed consent, 100 patients (31 male and 69 female, average age 65, range 35 to 85) were enrolled; demographic comparison between the two cohorts was similar. Exclusion criteria included inflammatory arthropathy, neuropathy, weight exceeding 250 pounds, radiographic coronal plane deformity greater than 15 degrees or extensive talar dome wear pattern (“flat top talus”). Prospective patient-reported outcomes, physical exam and standardized weightbearing ankle radiographs were obtained preoperatively, at 6 and 12 months postoperatively, and then at yearly intervals. Data collection included visual analog pain score (VAS), short form 36 (SF-36), foot and ankle disability index (FADI), short musculoskeletal functional assessment (SMFA) and AOFAS ankle-hindfoot score. Surgeries were performed by non-design team orthopaedic foot and ankle specialists with total ankle replacement expertise. Statistically analysis was performed by a qualified statistician. Results: At average follow-up of 4.5 years (range 2-6 years) complete clinical data and radiographs were available for 84 patients; 7 had incomplete data, one had died, 4 were withdrawn after enrolling but prior to surgery and 4 were lost to follow-up. In all outcome measures, the entire cohort demonstrated statistically significant improvements from preoperative evaluation to most recent follow-up. There was no statistically significant difference in improvement in clinical outcomes between the two groups. Radiographically, tibial lucency/cyst formation was 26.8% and 20.9% for MB-TAR and FB-TAR, respectively. Tibial settling/subsidence occurred in 7.3% of MB-TAR. Talar lucency/cyst formation occurred in 24.3% and 2.0% of MB-TAR and FB-TAR, respectively. Talar subsidence was observed in 21.9% and 2.0% of MB-TAR and FB-TAR, respectively. Re-operations were performed in 8 MB-TAR and 3 FB-TAR, with the majority of procedures being to relieve impingement or treat cysts and not to revise or remove metal implants. Conclusion: For the first time, with a high level of evidence, our study confirms that patient reported and clinical outcomes are favorable for both designs and that there is no significant difference in clinical improvement between the two implants. The incidence of lucency/cyst formation was similar for MB-TAR and FB-TAR for the tibial component, but the MB-TAR had greater talar lucency/cyst formation and tibial and talar subsidence. As has been suggested in previous studies, clinical outcomes do not correlate with radiographic findings. Re-operations were more common for MB-TAR and in the majority of cases were to relieve impingement or treat cysts rather than revise or remove metal implants.


2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0001
Author(s):  
Emily M. Abbott ◽  
Zoe Merchant ◽  
Erica Lee ◽  
Sadie M. Abernathy ◽  
Charles Hammer ◽  
...  

Category: Ankle Arthritis Introduction/Purpose: Total ankle replacement (TAR) is common tool used by the foot and ankle specialist to treat end stage ankle arthritis. Current data about ankle motion following TAR is derived from gait analysis utilizing external markers. Utilizing Xray Reconstruction of Moving Morphology (XROMM), which combines 3-D mapping technology with biplanar fluoroscopy in vivo to visualize true skeletal motion, we can evaluate true motion of TAR implants. Current TAR replacement systems are either mobile bearing or fixed bearing. We hypothesized that subjects implanted with a fixed bearing prosthesis would exhibit less tibiotalar rotation and translation than subjects implanted with a mobile bearing prosthesis. Methods: Six subjects with total ankle replacement at least one-year post implantation gave informed consent before participating (IRB #H16496). Three subjects with a mobile bearing prosthesis with an average age 63.3+-11.1 yrs were compared to three matched subjects with a fixed bearing prosthesis with an average age of 64.7+-1.5 yrs. Utilizing 3D slicer software, lower body CT scans for each subject were evaluated to create 3D models of the foot and ankle bones and implant components. All subjects walked for several trials at a self-selected pace along a walkway while their foot and ankle motions were captured by a high-speed biplanar fluoroscopic x-ray motion analysis (XMA) system. The 3D models were combined with the x-ray images within a 3D animation platform and rotoscoped to resolve accurate kinematic motions at the tibiotalar joint during stance phase of gait. We examined for differences between the two groups using a two-sample t-test (p<0.05). Results: Subjects with a mobile-bearing prosthesis demonstrated mean ROM’s of 7.4+-1.1°, 5.3+-2.3° and 7.1+-4.3° for dorsiflexion/plantarflexion, inversion/eversion, and internal/external rotation, respectively. Subjects with a fixed bearing ankle prosthesis did not exhibit significantly different mean ROM’s for dorsiflexion/plantarflexion (9.1+-4.0°, p=0.35), inversion/eversion (4.4+-2.1°, p=0.42), and internal/external rotation (9.0+-3.4°, p=0.35), respectively. Subjects with a fixed bearing prosthesis displayed significantly more translation along the anteroposterior (3.6+-1.2mm, p<0.01) and mediolateral (2.2+-0.7mm, p<0.01) axes compared to the mobile bearing prosthesis (1.8+-1.2mm and 1.3+-0.8mm, respectively). Conclusion: Our preliminary results indicate that mobile and fixed bearing prosthesis provides similar angular motion at the tibiotalar joint, however, the fixed bearing prosthesis exhibits greater translational motion during walking. Further, there is the same amount of internal and external translation with both component designs. The implications of this work on success or failure of current implant designs is beyond the scope of this study but this work will provide the basis for future studies to help determine optimal future total ankle replacement designs.


2021 ◽  
pp. 107110072110538
Author(s):  
Georg Hauer ◽  
Reinhard Hofer ◽  
Markus Kessler ◽  
Jan Lewis ◽  
Lukas Leitner ◽  
...  

Background: The aim of this study was to assess the outcome of total ankle replacement (TAR) regarding revision rates by comparing clinical studies of the last decade to data displayed in arthroplasty registers. The secondary aim was to evaluate whether dependent clinical studies show a superior outcome to independent publications. Additionally, revision rates of mobile bearing implants (MB-TARs) were compared to those of fixed bearing implants (FB-TARs). Methods: Clinical studies on TARs between 2010 and 2020 were systematically reviewed, with the endpoint being a revision for any reason. The parameter “revision rate per 100 observed component years (CYs)” was calculated for each publication. The pooled revision rate for clinical studies was compared to the data reported in arthroplasty registers. In a second step, revision rates were subdivided and analyzed for independent and dependent publications and for FB-TARs and MB-TARs. Results: A total of 43 publications met the inclusion criteria comprising 5806 TARs. A revision rate of 1.8 per 100 observed CYs was calculated, corresponding to a 7-year revision rate of 12.6%. The 3 arthroplasty registers included showed revision rates ranging from 8.2% to 12.3% after 7 years. No significant difference between dependent and independent publications nor between FB-TARs and MB-TARs was detected. Conclusion: Revision rates of clinical studies and arthroplasty registers are comparable. Surgeons can compare their own revision rates with those from this study. Dependent studies do not seem to be biased, and no superiority for one bearing type can be described. Level of Evidence: Level III, systematic review of level III studies


2019 ◽  
Vol 40 (11) ◽  
pp. 1239-1248 ◽  
Author(s):  
James A. Nunley ◽  
Samuel B. Adams ◽  
Mark E. Easley ◽  
James K. DeOrio

Background: Outcomes of total ankle replacement for the treatment of end-stage ankle arthritis continue to improve. Debate continues whether a mobile-bearing total ankle replacement (MB-TAR) or a fixed-bearing total ankle replacement (FB-TAR) is superior, with successful outcomes reported long term for MB-TAR and at intermediate- to long-term follow-up for newer generation FB-TAR. Although comparisons between the 2 total ankle designs have been reported, to our knowledge, no investigation has compared the 2 designs with a high level of evidence. This prospective, randomized controlled trial conducted at a single institution compares patient satisfaction, functional outcomes, and radiographic results of the mobile-bearing STAR and the fixed-bearing Salto-Talaris in the treatment of end-stage ankle arthritis. Methods: Between November 2011 and November 2014, adult patients with end-stage ankle osteoarthritis failing nonoperative treatment were introduced to the study. With informed consent, 100 patients (31 male and 69 female, average age 65 years, range 35-85 years) were enrolled; a demographic comparison between the 2 cohorts was similar. Exclusion criteria included inflammatory arthropathy, neuropathy, weight exceeding 250 pounds, radiographic coronal plane deformity greater than 15 degrees, or extensive talar dome wear pattern (“flat-top talus”). Prospective patient-reported outcomes, physical examination, and standardized weightbearing ankle radiographs were obtained preoperatively, at 6 and 12 months postoperatively, and then at yearly intervals. Data collection included visual analog pain score, Short Form 36, Foot and Ankle Disability Index, Short Musculoskeletal Functional Assessment, and American Orthopaedic Foot & Ankle Society ankle-hindfoot score. Surgeries were performed by a nondesign team of orthopedic foot and ankle specialists with total ankle replacement expertise. Statistical analysis was performed by a qualified statistician. At average follow-up of 4.5 years (range, 2-6 years) complete clinical data and radiographs were available for 84 patients; 7 had incomplete data, 1 had died, 4 were withdrawn after enrolling but prior to surgery, and 4 were lost to follow-up. Results: In all outcome measures, the entire cohort demonstrated statistically significant improvements from preoperative evaluation to most recent follow-up with no statistically significant difference between the 2 groups. Radiographically, tibial lucency/cyst formation was 26.8% and 20.9% for MB-TAR and FB-TAR, respectively. Tibial settling/subsidence occurred in 7.3% of MB-TAR. Talar lucency/cyst formation occurred in 24.3% and 2.0% of MB-TAR and FB-TAR, respectively. Talar subsidence was observed in 21.9% and 2.0% of MB-TAR and FH-TAR, respectively. Reoperations were performed in 8 MB-TARs and 3 FH-TARs, with the majority of procedures being to relieve impingement or treat cysts and not to revise or remove metal implants. Conclusion: With a high level of evidence, our study found that patient-reported and clinical outcomes were favorable for both designs and that there was no significant difference in clinical improvement between the 2 implants. The incidence of lucency/cyst formation was similar for MB-TAR and FH-TAR for the tibial component, but the MB-TAR had greater talar lucency/cyst formation and tibial and talar subsidence. As has been suggested in previous studies, clinical outcomes do not necessarily correlate with radiographic findings. Reoperations were more common for MB-TAR and, in most cases, were to relieve impingement or treat cysts rather than revise or remove metal implants. Level of Evidence: Level I, prospective randomized study.


2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002
Author(s):  
Camilla Maccario ◽  
Cristian Indino ◽  
Luigi Manzi ◽  
Federico Giuseppe Usuelli ◽  
Claudia Di Silvestri

Category: Ankle, Ankle Arthritis Introduction/Purpose: Primary ankle osteoarthritis is very uncomon, in fact 70-78% of the case ankle arthritis has a post- traumatic cause. Ankle arthrodesis (AA), has been considered a reliable procedure for resolution of ankle osteoarthritis. Recent modifications in Total ankle replacement (TAR) designs have challenged the perception that AA is the treatment of choice for end-stage ankle arthritis. Trabecular Metal Total Ankle system is a fixed-bearing prosthesis. The new design is flanked by use of new materials. The tibial articular surface is constructed of highly crosslinked UHMWPE and Trabecular Metal lining the talar and the tibial base component. The purpose of this retrospective study was to show the preliminary result in 31 patients underwent to ankle replacement using Zimmer Trabecular Metal Total Ankle system. Methods: We retrospectively assessed prospectively collected data on the initial cohort of 31 patients undergoing TAR with this implant. Clinical evaluation was determined pre and postoperatively for a minimum of 24 months after surgery. Pain was rated using the visual analogue scale (VAS). Functional results were assessed as well as ankle range of motion (ROM). Clinical outcomes used where the Short Form SF-12 Quality of Life score, the American Foot and Ankle Society (AOFAS). The imaging follow-up included ankle radiographs done at 6, 12 and 24 months. Radiological parameters were angles??(normal values 90 +- 2),?? (normal value 85 +- 2),??? normal values 20 +- 2) and TTratio? normal values: 27% to 42%). Results: The study included 31 ankles of TM Ankle Replacement in 31 consecutive patients over a period of 2 years (2013–2015). Out of 31 patients, 13 were females and 18 were males (average age 49.4 years, range, 30–75 years). All procedures were performed by a single surgeon. The ROM plantarflexion and dorsiflexion improved significantly (p <0.001) at the last follow up. The mean VAS pain score decreased significantly from 7.42 points (range 4 – 10 points) preoperatively to 1.42 points (range, 0 - 3 points) at the time of the latest follow-up (p <0.001). AOFAS and SF-12 scores both improved from postoperatively to the last follow up. (Table 1). We noted stable implants based on our radiographic parameters, with no corrections loosening. (Table 2) Conclusion: Our study evaluated the new fixed bearing Zimmer TM total ankle replacement approved by the US FDA in 2012 and is the first studies to evaluate the clinical and radiographic outcomes of this prosthesis. Of 31 ankles treated with a new transfibular arthroplasty system, only two asymptomatic fibular delayed union were registered. No implant failure was noted at 24 months postoperatively. Four ankles underwent secondary surgery for symptomatic fibular hardware with good outcome. The findings suggest that this total ankle system is safe and effective at short-term follow-up.


2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0005
Author(s):  
Francesco Granata ◽  
Camilla Maccario ◽  
Luigi Manzi ◽  
Eric Tan ◽  
Federico Giuseppe Usuelli

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.


2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0003
Author(s):  
Natalie Nielsen ◽  
Austin Sanders ◽  
Joseph Nguyen ◽  
Constantine Demetracopoulos

Category: Ankle Arthritis Introduction/Purpose: Placement of the talar component in total ankle replacement (TAR) is technically challenging and malposition can occur. Implant alignment can affect both contact stresses at the articulation of the prosthesis, as well as forces at the bone implant interface, and survivorship of the implant. In mobile bearing implants, postoperative pain relief and functional outcome correlates with sagittal position of the talar component. The purpose of this study is to evaluate the sagittal alignment of the talar component between two fixed bearing total ankle replacements and determine the effect of alignment on patient outcomes. Methods: We performed a retrospective review of total ankle replacements at a single institution over a seven-year period. Seventy-one patients who underwent a fixed bearing TAR (Salto Talaris, Integra LifeSciences, and INBONE, Wright Medical) with two year minimum followup were included. Preoperative and one year postoperative radiographs were assessed to determine sagittal alignment of the talar component. The preoperative sagittal alignment was measured as the tibial-axis-to-talus ratio (T-T ratio) and the postoperative sagittal alignment was measured as the A-P offset ratio. Postoperative sagittal alignment was categorized as neutral (A-P offset ratio <0.1, N=39) or anterior (A-P offset ratio >0.1, N=32). Functional outcomes were assessed at 2 years utilizing SF12 scores and the FAOS outcome score, which has been previously validated for ankle arthritis. Differences in sagittal alignment between the two implant types and differences in postoperative outcome scores were assessed using T-tests. Interobserver reliability was assessed using intraclass correlation coefficient. Results: Interobserver reliability for the preoperative sagittal alignment using the T-T ratio had very good agreement, while the postoperative A-P offset measurement had only fair/moderate agreement. Preoperatively, there was no difference in the T-T ratio amongst patients receiving a Salto Talaris or INBONE implant. Postoperatively, patients with a Salto Talaris implant have a greater AP offset ratio than patients with an INBONE implant (p <0.01). There was no difference in FAOS or SF12 MCS/PCS scores between postoperative neutral and anterior sagittal alignment groups. Conclusion: Preoperative sagittal alignment can be reliably assessed using the T-T offset ratio. The A-P offset ratio is somewhat less reliable as a measure of postoperative sagittal alignment in fixed bearing implants. Patients with INBONE implants had more neutral sagittal alignment postoperatively. Differences in alignment between the two implants may relate to anterior-posterior coverage of the tibial component and the fixed bearing nature of the prostheses. Patient reported outcome scores did not differ between neutral and anterior sagittal alignment groups.


2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0036
Author(s):  
Roxa Ruiz ◽  
Christine Schweizer ◽  
Nicola Krähenbühl ◽  
Beat Hintermann

Category: Ankle, Ankle Arthritis Introduction/Purpose: The interface between the polyethylene (PE) inlay and the tibial component in mobile-bearing total ankle replacement (TAR) systems may allow the talus to seek its position according to the individual anatomy. However, chronic overload and/or incompetence of soft tissue may allow medial and/ or lateral translation of the talar component over time. This typically results in medial and/ or lateral gutter pain as well as pain along the syndesmosis. The purpose of this study was to assess the effect of tibial component exchange and conversion from a mobile-bearing into a fixed-bearing TAR system in patients with coronal plane instabilities TAR. Methods: A consecutive series of 30 ankles (29 patients; age 65.6 [48.9 – 86.1]; male, 23; female, 7) with coronal plane instabilities underwent revision TAR with exchange of a mobile-bearing (Hintermann Series, H3) into a fixed-bearing (Hintermann Series, H2) TAR system. Patients presented with a medial (n = 12) or lateral (n = 9) translation of the talar component, or a varus (n = 4) or valgus (n = 5) instability with subsequent tilt of the talar component. After removing the tibial component and PE inlay, a tibial osteotomy was performed and 1 to 2 mm of the distal tibia removed. A tibial component of the H2 total ankle system was inserted. While holding the foot in neutral position, the PE inlay was locked to the tibial component in the appropriate position. Functional outcome and pain were recorded to evaluate clinical outcome, and standard radiographs under fluoroscopy were taken for radiographic assessment. Results: All but one of the remaining 28 patient showed significant improvement of pain (P<0.05). Preoperative gutter pain disappeared completely in 20 ankles (71.4%), and partially in 8 ankles (18.6%). The AOFAS Hindfoot Score improved from 54.3 (range, 21 to 90) preoperatively to 74.0 (range, 48 to 92) at latest follow-up (P<0.05). Radiographic assessment showed firm osteointegration in all patients with the talar component centralized in the ankle mortise, and a free medial and lateral gutter without tilt of talar component (Figure 1). One patient with bilateral revision TAR was affected by a bilateral deep infection of both ankles 9 months after surgery subsequent to a severe pneumonia. Both ankles were removed and replaced by a cement spacer. Conclusion: Converting a mobile-bearing into a fixed-bearing TAR system has shown to be effective in the treatment of patients with coronal plane instabilities following TAR. Allowing the PE inlay to adapt its position according to the talar component before definitive fixation to the tibial component of the H2 series, saved having to replace the talar component. Future long-term studies however are needed to identify significant benefits of this novel total ankle concept in primary and revision TAR.


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