Assessment of Intraoperative of Range of Motion after Total Ankle Replacement: Radiographic Cohort Study

Category: Ankle Arthritis Introduction/Purpose: One of the proposed benefits of total ankle replacement (TAR), when compared to ankle fusion is the restoration of the functional range of motion (ROM) of the ankle. Preservation of ankle motion may improve quality of life as evidenced by patient-reported outcome measures (PROMs). However, some studies have shown a lack of improvement of ankle range of motion after the postoperative recovery period, despite satisfactory motion being observed intra-operatively. The objective of this study was to radiographically compare intraoperative and pre-operative ankle range of motion. Methods: This single-center retrospective study compared 56 patients with an average age of 62.27 years who underwent primary TAR with one of four different implants between March and December 2019. 48% of patients had post-traumatic arthritis secondary to an ankle fracture, 50% had post-traumatic arthritis secondary to instability. Seventy-two percent of patients had an associated Achilles lengthening, 16% had an associated lateral ligament reconstruction procedure. Standardized weight-bearing maximum dorsiflexion and plantarflexion sagittal radiographs were obtained pre-operatively. In order to record intraoperative fluoroscopic imaging, the primary surgeon passively placed the ankle into maximum dorsiflexion and plantarflexion. Intraoperatively, the neutral lateral position of the ankle was determined after the replacement when the talus was in perfect lateral view. All angular measurements were made using the PACS system (Picture Archiving and Communication System). The change in range of motion was analyzed using a paired t-test with a significance level of 0.05. Results: The intraoperative range of motion increased significantly for all measures when compared to the pre-operative range of motion. The average pre-operative global arc of motion significantly increased from 20.21 degrees to 38.49 degrees intra- operatively (p=2.45x10-18, t(55)=2.00). The average pre-operative plantar flexion significantly increased from 12.80 degrees to 25.50 degrees intra-operatively (p=2.56x10-15, t(55)=2.00). The average pre-operative dorsiflexion significantly increased from 7.28 degrees to 13.35 degrees intra-operatively (p=4.68x10-6 t(55)=2.00). Patients who had an Achilles lengthening had an average increase in the global arc of motion of 18.78 degrees; patients who did not have an Achilles lengthening had an average increase of 17.02 degrees (p=0.562, t(31)=2.04). Overall, 93% of patients increased their range of motion after their total ankle replacement. Conclusion: This study demonstrates notable improvement in ankle range of motion intraoperatively following total ankle replacement, especially in plantarflexion. Total Ankle Replacement provides an improvement in the functional range of motion of the ankle intraoperatively, suggesting that the loss of motion observed in previous studies may occur during the postoperative period. The present study may help inform and adjust the postoperative rehabilitation protocol after total ankle replacement in order to avoid losing the amplitude of motion gained during the operation.

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Early Clinical and Radiographic Outcomes of Trabecular Metal Total Ankle Using Transfibular Approach

Foot & Ankle Orthopaedics ◽

10.1177/2473011417s000107 ◽

2017 ◽

Vol 2 (3) ◽

pp. 2473011417S0001 ◽

Cited By ~ 1

Author(s):

Alexej Barg ◽

Charles Saltzman

Keyword(s):

Range Of Motion ◽

Weight Bearing ◽

Total Ankle Replacement ◽

Trabecular Metal ◽

Non Union ◽

Early Loosening ◽

Early Results ◽

Ankle Replacement ◽

Patient Reported

Category: Ankle, Ankle Arthritis Introduction/Purpose: In the last two decades, total ankle replacement (TAR) has gained more acceptance as a treatment option in patients with end-stage ankle osteoarthritis. However, there is a lack of literature on TAR using a lateral transfibular approach. Therefore, we sought to report early clinical and radiographic results of a patient cohort treated with TAR using a lateral transfibular approach by a single surgeon. Methods: Fifty-five primary total ankle arthroplasties using the Zimmer trabecular metal implant were performed in 54 patients (29 men and 25 women; mean age, 67.0 years) from October 2012 to December 2014. Clinical assessment including pain evaluation and measurement of ankle range of motion was done preoperatively and at the latest follow-up. Weight-bearing radiographs were used to determine the angular alignment of the tibial and talar components and to analyze the bone-implant interface. Intraoperative and postoperative complications, revision surgeries, and failures were evaluated. Results: Implant survival was 93% at 36 months follow-up. There were 3 revisions of a tibial component due to aseptic loosening. In 10 of 55 procedures, a secondary procedure was performed during follow-up. Mean follow-up duration was 26.6 ± 4.2 months. No delayed union or non-union was observed for fibula healing. The average VAS pain score decreased significantly from 7.9 ± 1.3 to 0.8 ± 1.2. The average total range of motion increased significantly from 22.9° ± 11.8° to 40.2° ± 11.8°. Conclusion: Early results of Zimmer trabecular metal total ankle replacement demonstrated improved patient-reported outcomes and increased ankle motion at a minimum follow-up of one year. In the first 55 consecutive cases, the fibular osteotomy required for access to the ankle healed without complications. Painful early loosening requiring revision due to lack of bony ingrowth was seen in 3 of 55 cases.

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Brazilian Total Ankle Replacement Experience

Foot & Ankle Orthopaedics ◽

10.1177/2473011420s00116 ◽

2020 ◽

Vol 5 (4) ◽

pp. 2473011420S0011

Author(s):

Daniel Baumfeld ◽

André V. Lemos ◽

César E. Martins ◽

Caio A. Nery

Keyword(s):

Personal Data ◽

National Registry ◽

Total Ankle Replacement ◽

First Year ◽

Ankle Arthroplasty ◽

Ankle Replacement ◽

Surgeon Experience ◽

Post Traumatic ◽

Traumatic Arthritis ◽

Post Infectious

Category: Ankle Arthritis Introduction/Purpose: Brazil experiences a late participation in total ankle arthroplasty, which could have positive and negative aspects. The positive view argues about the modern implants that Brazil has received in the past years, skipping the early TAR generation who present more complications and low survival rate in the literature. The negative aspects are related to gap of experience, Brazilian surgeon could not participate in the development of the technique and implants designs during all these years. This paper present the aspects of the Brazilian experience with total ankle replacement since the earliest procedures performed. Methods: Data since the first series of TARs in Brazil were colect from university institution, personal data base from surgeons and previous publication, survivalship, complications, number of each implant and implant availability were recorded. Results: In Brazil, indications for TAR are not so different from around the world, the data we had access demonstrate 65% of post-traumatic arthritis, 26 % of inflammatory arthritis, 2% post-infectious arthritis and 7 % of primary arthritis. In fortheen years 263 surgeries were performed, in different parts of the country, but only one surgeon performed 43 cases (27,3% of the total). Table 1 demonstrate the number of procedures performed per year. Survivor rate of each implant available in the country in the first year were 94%, 86,19% in the second year, 82,84% in the third year, 81,62% in the fourth year and 71,47% in the fifth year. Conclusion: In Brazil there are limited and different ankle arthroplasty systems available for use. The procedure itself continues to be technically demanding and require surgical sophistication and expertise. A national registry to justify the procedure indication; report the outcomes and survivorship has not been developed. This procedure is growing around the county, as well as the surgeon experience, but we should remember that TAR is not for every patient and that the appropriate indication, based on the evidence available, is fundamental to obtaining durable and predictable outcomes. [Table: see text]

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Does Post-Traumatic Arthritis Produce Poorer 5 Year Patient Outcomes Following Mobile-Bearing Total Ankle Replacement?

Foot & Ankle Orthopaedics ◽

10.1177/2473011416s00167 ◽

2016 ◽

Vol 1 (1) ◽

pp. 2473011416S0016

Author(s):

Sarah E. Johnson-Lynn ◽

Jayasree R. Ramaskandhan ◽

Malik S. Siddique

Keyword(s):

Patient Outcomes ◽

Mobile Bearing ◽

Total Ankle Replacement ◽

Ankle Replacement ◽

Post Traumatic ◽

Traumatic Arthritis

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

Foot & Ankle Orthopaedics ◽

10.1177/2473011419s00367 ◽

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.

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Comparison of Total Ankle Replacement and Ankle Arthrodesis During the Recovery Period

Foot & Ankle Orthopaedics ◽

10.1177/2473011417s000147 ◽

2017 ◽

Vol 2 (3) ◽

pp. 2473011417S0001

Author(s):

Justin Colanese ◽

Jeremy J. McCormick ◽

Jeffrey Johnson ◽

Sandra Klein

Keyword(s):

Chart Review ◽

Recovery Period ◽

Ankle Arthrodesis ◽

Total Ankle Replacement ◽

Study Patient ◽

Measurement Information ◽

Ankle Arthritis ◽

Retrospective Case ◽

Ankle Replacement ◽

Patient Reported

Category: Ankle, Ankle Arthritis Introduction/Purpose: Two reliable surgical alternatives exist for end-stage ankle arthritis, ankle arthrodesis and total ankle replacement. Several comparative studies have shown similar clinical results between the two procedures at intermediate-term follow-up (2 to 6 years). Despite this comparative literature, no studies have been dedicated to determining which of the two procedures allows better function and pain during the recovery period (the first 6 months following the procedure). This information is especially beneficial to patients for whom a more difficult and longer recovery is particularly adverse, such as elderly patients or patients with medical comorbidities. It is also unclear if pain or dysfunction during the recovery period correlates with intermediate-term complications such as nonunion or prosthetic loosening. Methods: This is a single site retrospective case-control study. Patient-Reported Outcomes Measurement Information System (PROMIS) scores have been completed by patients at the orthopedic foot and ankle clinic at each visit since October 2014. Patients who have undergone either a total ankle replacement or an ankle arthrodesis during that timeframe were evaluated to determine their level of pain, function, anxiety and depression at a given interval (from preoperative to 6 months) during their recovery. Data acquisition was via chart review. Exclusion criteria included Charcot neuroarthropathy and inadequate data. Results: 138 procedures (58 total ankle replacements, 80 ankle arthrodeses) were performed at our institution during the study period. Chart review of patients meeting inclusion criteria is currently being conducted to record PROMIS scores, adjuvant procedures, complications, return to work and post-operative protocol during the first 6 months following the procedure. Data analysis will be undertaken, to detect a minimally important difference between PROMIS scores, with a 95% confidence interval and power of 0.8, the minimal sample size was calculated to be 44 subjects in each group. For patients who developed a complication from surgery (non-union, implant loosening, infection, etc.), scores will be reviewed to determine if abnormal PROMIS scores early on in the recovery period correlate with future complications. Conclusion: Patient pain and function during the first 6 months following surgery is an important consideration for those contemplating both ankle arthrodesis and replacement as options. Data collected from this study to be completed by Spring 2017 will help to clarify if differences between the two procedures exist.

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Living With Both a Total Ankle Replacement and an Ankle Fusion: A Qualitative Study From the Patients’ Perspective

Foot & Ankle International ◽

10.1177/10711007211004447 ◽

2021 ◽

pp. 107110072110044

Author(s):

Catherine Conlin ◽

Ryan M. Khan ◽

Ian Wilson ◽

Timothy R. Daniels ◽

Mansur Halai ◽

...

Keyword(s):

Hospital Setting ◽

Case Series ◽

Total Ankle Replacement ◽

Qualitative Description ◽

Level Of Evidence ◽

Foot Placement ◽

Advantages And Disadvantages ◽

Ankle Fusion ◽

Ankle Replacement ◽

Patient Reported

Background: Total ankle replacement (TAR) and ankle fusion are effective treatments for end-stage ankle arthritis. Comparative studies elucidate differences in treatment outcomes; however, the literature lacks evidence demonstrating what outcomes are important to patients. The purpose of this study was to investigate patients’ experiences of living with both a TAR and ankle fusion. Methods: This research study used qualitative description. Individuals were selected from a cohort of patients with TAR and/or ankle fusion (n = 1254). Eligible patients were English speaking with a TAR and contralateral ankle fusion, and a minimum of 1 year since their most recent ankle reconstruction. Surgeries were performed by a single experienced surgeon, and semistructured interviews were conducted by a single researcher in a private hospital setting or by telephone. Ankle Osteoarthritis Scale (AOS) scores, radiographs, and ancillary surgical procedures were collected to characterize patients. Themes were derived through qualitative data analysis. Results: Ten adults (8 men, 2 women), ages 59 to 90 years, were included. Average AOS pain and disability scores were similar for both surgeries for most patients. Participants discussed perceptions of each reconstructed ankle. Ankle fusions were considered stable and strong, but also stiff and compromising balance. TARs were considered flexible and more like a “normal ankle,” though patients expressed concerns about their TAR “turning” on uneven ground. Individuals applied this knowledge to facilitate movement, particularly during a first step and transitioning between positions. They described the need for careful foot placement and attention to the environment to avoid potential challenges. Conclusion: This study provides insight into the experiences of individuals living with a TAR and ankle fusion. In this unusual but limited group of patients, we found that each ankle reconstruction was generally perceived to have different characteristics, advantages, and disadvantages. Most participants articulated a preference for their TAR. These findings can help clinicians better counsel patients on expectations after TAR and ankle fusion, and improve patient-reported outcome measures by better capturing meaningful outcomes for patients. Level of Evidence: Level IV, case series.

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Clinical Radiographical Outcomes and Complications after a Brand-New Total Ankle Replacement Design through an Anterior Approach: A Retrospective at a Short-Term Follow Up

Journal of Clinical Medicine ◽

10.3390/jcm10112258 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2258

Author(s):

Massimiliano Mosca ◽

Silvio Caravelli ◽

Emanuele Vocale ◽

Simone Massimi ◽

Davide Censoni ◽

...

Keyword(s):

Mean Value ◽

Total Ankle Replacement ◽

P Value ◽

Ankle Osteoarthritis ◽

Ankle Replacement ◽

Patient Reported ◽

End Stage ◽

Term Performance ◽

Replacement Design

Recently, the progress in techniques and in projecting new prosthetic designs has allowed increasing indications for total ankle replacement (TAR) as treatment for ankle osteoarthritis. This retrospective work comprehended 39 subjects aged between 47 and 79 years old. The patients, observed for at least 12 months (mean follow up of 18.2 ± 4.1 months), have been evaluated according to clinical and radiological parameters, both pre- and post-operatively. The AOFAS and VAS score significantly improved, respectively, from 46.2 ± 4.8 to 93.9 ± 4.1 and from 7.1 ± 1.1 to 0.7 ± 0.5 (p value < 0.05). At the final evaluation, the mean plantarflexion passed from 12.2° ± 2.3° to 18.1° ± 2.4° (p value < 0.05) and dorsiflexion from a pre-operative mean value of 8.7° ± 4.1° to 21.7° ± 5.4° post-operatively (p value < 0.05). This study found that this new total ankle replacement design is a safe and effective procedure for patients effected by end-stage ankle osteoarthritis. Improvements have been demonstrated in terms of range of motion, radiographic parameters and patient-reported outcomes. However, further studies are needed to assess the long-term performance of these prostheses.

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Prospective Randomized Trial Comparing Mobile-Bearing and Fixed-Bearing Total Ankle Replacement

Foot & Ankle International ◽

10.1177/1071100719879680 ◽

2019 ◽

Vol 40 (11) ◽

pp. 1239-1248 ◽

Cited By ~ 4

Author(s):

James A. Nunley ◽

Samuel B. Adams ◽

Mark E. Easley ◽

James K. DeOrio

Keyword(s):

Mobile Bearing ◽

Cyst Formation ◽

Total Ankle Replacement ◽

Fixed Bearing ◽

Level Of Evidence ◽

Ankle Replacement ◽

Significant Difference ◽

Patient Reported ◽

End Stage

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.

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

Foot & Ankle Orthopaedics ◽

10.1177/2473011419s00049 ◽

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.

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