Accuracy of CT-Derived Patient-Specific Instrumentation for Total Ankle Arthroplasty: The Impact of the Severity of Preoperative Varus Ankle Deformity

Background Significant preoperative varus tibiotalar deformity was once believed to be a contraindication for total ankle arthroplasty (TAA). Our primary goal was to evaluate the influence of increasing preoperative varus tibiotalar deformity on the accuracy of final implant positioning using computed tomography (CT)-derived patient-specific guides for TAA. Methods Thirty-two patients with varus ankle arthritis underwent TAA using CT-derived patient-specific guides. Patients were subcategorized into varying degrees of deformity based on preoperative tibiotalar angles (0°-5° neutral, 6°-10° mild, 11°-15° moderate, and >15° severe). Postoperative weightbearing radiographs were used to measure coronal plane alignment of the tibial implant relative to the target axis determined by the preoperative CT template. Average follow-up at the time of data collection was 36.8 months. Results Average preoperative varus deformity was 6.06° (range: 0.66°-16.3°). Postoperatively, 96.9% (30/31) of patients demonstrated neutral implant alignment. Average postoperative tibial implant deviation was 1.54° (range: 0.17°-5.7°). Average coronal deviation relative to the target axis was 1.61° for the neutral group, 1.78° for the mild group, 0.94° for the moderate group, and 1.41° for the severe group (P = .256). Preoperative plans predicted 100% of tibial and talar implant sizes correctly within 1 size of actual implant size. Conclusion. Our study supports the claim that neutral postoperative TAA alignment can be obtained using CT-derived patient-specific instrumentation (PSI). Furthermore, final implant alignment accuracy with PSI does not appear to be impacted by worsening preoperative varus deformity. All but one patient (96.9%) achieved neutral postoperative alignment relative to the predicted target axis. Level of Evidence: Level IV, Clinical Case Series

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Hindfoot Alignment Change After Total Ankle Arthroplasty for Varus Osteoarthritis

Foot & Ankle International ◽

10.1177/1071100720970937 ◽

2020 ◽

pp. 107110072097093

Author(s):

Hyuck Sung Son ◽

Jung Gyu Choi ◽

Jungtae Ahn ◽

Bi O Jeong

Keyword(s):

Ankle Joint ◽

Case Series ◽

Deformity Correction ◽

Varus Deformity ◽

Total Ankle Arthroplasty ◽

Level Of Evidence ◽

Hindfoot Alignment ◽

Ankle Arthroplasty ◽

End Stage ◽

Surface Angle

Background: In patients with end-stage varus ankle osteoarthritis (OA), hindfoot varus malalignment resulting from the varus deformity of the ankle joint is common. Although total ankle arthroplasty (TAA) performed to correct varus deformity of the ankle joint has the effect of correcting hindfoot alignment, no reports to date have described how much hindfoot alignment correction can be achieved. The purpose of this study was to identify correlation between ankle deformity correction and hindfoot alignment change after performing TAA in patients with end-stage varus ankle OA. Methods: A total of 61 cases that underwent TAA for end-stage varus ankle OA and followed up for at least 1 year were enrolled for this study. Correlation between changes of tibial-ankle surface angle (TAS), talar tilt (TT), and tibiotalar surface angle (TTS) and changes of hindfoot alignment angle (HA), hindfoot alignment ratio (HR), and hindfoot alignment distance (HD) measured preoperatively and at postoperative year 1 was analyzed. Results: TAS, TT, and TTS changed from 83.9 ± 4.1 degrees, 5.8 ± 5.0 degrees, and 78.1 ± 5.9 degrees, respectively, before operation to 89.2 ± 2.1 degrees, 0.4 ± 0.5 degrees, and 88.7 ± 2.3 degrees, respectively, after operation. HA, HR, and HD also changed from −9.2 ± 4.6 degrees, 0.66 ± 0.18, and −11.2 ± 6.9 mm to −3.7 ± 4.1 degrees, 0.48 ± 0.14, and −5.0 ± 5.3 mm. All the changes were statistically significant ( P < .001, respectively). The regression slope of correlation was 0.390 ( R2 = 0.654) between TTS and HA; 0.017 ( R2 = 0.617) between TTS and HR; and 0.560 ( R2 = 0.703) between TTS and HD. Conclusion: In patients with end-stage varus ankle OA, changes of hindfoot alignment could be predicted based on degree of ankle deformity corrected with TAA. Level of Evidence: Level IV, case series.

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Patient-specific instrumentation (PSI) in total ankle arthroplasty: a systematic review

International Orthopaedics ◽

10.1007/s00264-021-05145-8 ◽

2021 ◽

Author(s):

Qiuyuan Wang ◽

Nianfei Zhang ◽

Wanshou Guo ◽

Weiguo Wang ◽

Qidong Zhang

Keyword(s):

Systematic Review ◽

Total Ankle Arthroplasty ◽

Patient Specific ◽

Ankle Arthroplasty ◽

Patient Specific Instrumentation

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Radiographic and Clinical Outcomes of the Salto Talaris Total Ankle Arthroplasty

Foot & Ankle International ◽

10.1177/1071100720947030 ◽

2020 ◽

Vol 41 (12) ◽

pp. 1519-1528

Author(s):

Jonathan Day ◽

Jaeyoung Kim ◽

Martin J. O’Malley ◽

Constantine A. Demetracopoulos ◽

Jonathan Garfinkel ◽

...

Keyword(s):

Clinical Outcomes ◽

Case Series ◽

Total Ankle Arthroplasty ◽

Retrospective Case ◽

Level Of Evidence ◽

Ankle Arthroplasty ◽

Patient Reported ◽

The Mean ◽

Component Revision

Background: The Salto Talaris is a fixed-bearing implant first approved in the US in 2006. While early surgical outcomes have been promising, mid- to long-term survivorship data are limited. The aim of this study was to present the survivorship and causes of failure of the Salto Talaris implant, with functional and radiographic outcomes. Methods: Eighty-seven prospectively followed patients who underwent total ankle arthroplasty with the Salto Talaris between 2007 and 2015 at our institution were retrospectively identified. Of these, 82 patients (85 ankles) had a minimum follow-up of 5 (mean, 7.1; range, 5-12) years. The mean age was 63.5 (range, 42-82) years and the mean body mass index was 28.1 (range, 17.9-41.2) kg/m2. Survivorship was determined by incidence of revision, defined as removal/exchange of a metal component. Preoperative, immediate, and minimum 5-year postoperative AP and lateral weightbearing radiographs were reviewed; tibiotalar alignment (TTA) and the medial distal tibial angle (MDTA) were measured to assess coronal talar and tibial alignment, respectively. The sagittal tibial angle (STA) was measured; the talar inclination angle (TIA) was measured to evaluate for radiographic subsidence of the implant, defined as a change in TIA of 5 degrees or more from the immediately to the latest postoperative lateral radiograph. The locations of periprosthetic cysts were documented. Preoperative and minimum 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscales were compared. Results: Survivorship was 97.6% with 2 revisions. One patient underwent tibial and talar component revision for varus malalignment of the ankle; another underwent talar component revision for aseptic loosening and subsidence. The rate of other reoperations was 21.2% ( n = 18), with the main reoperation being exostectomy with debridement for ankle impingement ( n = 12). At final follow-up, the average TTA improved 4.4 (± 3.8) degrees, the average MDTA improved 3.4 (± 2.6) degrees, and the average STA improved 5.3 (± 4.5) degrees. Periprosthetic cysts were observed in 18 patients, and there was no radiographic subsidence. All FAOS subscales demonstrated significant improvement at final follow-up. Conclusions: We found the Salto Talaris implant to be durable, consistent with previous studies of shorter follow-up lengths. We observed significant improvement in radiographic alignment as well as patient-reported clinical outcomes at a minimum 5-year follow-up. Level of Evidence: Level IV, retrospective case series.

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Mechanical and Anatomical Axis in Total Ankle Arthroplasty

Foot & Ankle Orthopaedics ◽

10.1177/2473011418s00089 ◽

2018 ◽

Vol 3 (3) ◽

pp. 2473011418S0008

Author(s):

Ali-Asgar Najefi ◽

Andrew Goldberg

Keyword(s):

Lower Limb ◽

Mechanical Axis ◽

Normal Group ◽

Total Ankle Arthroplasty ◽

Coronal Plane ◽

Patient Specific ◽

Ankle Arthroplasty ◽

Patient Specific Instrumentation ◽

Significant Difference ◽

Anatomical Axis

Category: Ankle Arthritis Introduction/Purpose: Inadequate correction of alignment in the coronal, sagittal or axial planes will inevitably lead to failure of the Total Ankle Arthroplasty (TAA). The mechanical axis of the lower limb (MAL), the mechanical axis of the tibia (MAT) and the anatomical axis of the tibia (AAT) are three recognized coronal plane measurements using plain radiography. The relationship between anatomical and mechanical axes depends on the presence of femoral or tibial deformities from trauma or inherited conditions, or previous corrective or replacement surgery. Ankle arthroplasty relies heavily on preoperative radiographs or CT scans and the purpose of this study was to assess whether MAL, MAT and AAT are the same in a cohort of patients upon which placement of TAA is considered. Methods: We analysed 75 patients operated on between 2015 and 2016 at a specialist tertiary centre for elective orthopaedic surgery. All patients had a pre-operative long leg radiograph. They were split into 2 groups. The first group had known deformity proximal to the ankle (such as previous tibial or femoral fracture, severe arthritis, or previous reconstructive surgery) and the second group had no clinically detectable deformity. The MAL, MAT and AAT were assessed and the difference between these values was calculated. Results: There were 54 patients in the normal group, and 21 patients in the deformity group. Overall, 25 patients(33%) had a difference between all three axes of less than 1 degree. In 33 patients(44%), there was a difference in one of the axes of ≥2 degrees. There was no significant difference between MAT and AAT in patients in the normal group(p=0.6). 95% of patients had a difference of <1 degree. There was a significant difference between the MAT and AAT in patients in the deformity group(p<0.01). In the normal group, 39 patients(73%) had a difference of <2 degrees between the AAT and MAL. In the deformity group, only 10 patients (48%) had a difference of <2 degrees.In fact, 24% of patients had a difference ≥3 degrees. Conclusion: Malalignment in the coronal plane in TAA may be an issue that we have not properly addressed. Up to 66% of patients without known deformity may have a TAA that is placed at least 1 degree incorrectly relative to the MAL. We recommend the use of full-length lower limb radiographs when planning a TAA in order to plan the placement of implants. The decision to perform extramedullary referencing, intramedullary referencing, or patient specific Instrumentation must be part of the pre-operative planning process.

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Quality of Modern Total Ankle Arthroplasty Research

Foot & Ankle Orthopaedics ◽

10.1177/2473011418s00160 ◽

2018 ◽

Vol 3 (3) ◽

pp. 2473011418S0016

Author(s):

Daniel Bohl ◽

Emily Vafek ◽

Simon Lee ◽

Johnny Lin ◽

George Holmes ◽

...

Keyword(s):

Cohort Studies ◽

Case Reports ◽

Case Series ◽

The United States ◽

Total Ankle Arthroplasty ◽

Ankle Arthritis ◽

Level Of Evidence ◽

Ankle Arthroplasty ◽

End Stage

Category: Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty (TAA) is gaining popularity as an alternative to ankle arthrodesis in the setting of end-stage ankle arthritis. However, compared to hip and knee arthroplasty, there is a relative dearth of evidence to support its use. This study assesses the quality of literature surrounding modern TAA designs. Methods: A search of all peer-reviewed, English-language journals was conducted to identify publications involving TAA. The initial search identified 444 articles published during 2006-2016. Of these, 182 were excluded because they were not clinical outcomes studies, 46 because the TAA implant was no longer available, and 15 because the primary outcome of the study was not related to TAA, leaving 201 articles for analysis. Results: No Level I studies were identified. Seventeen (8%) studies were Level II, 48 (24%) Level III, 128 (64%) Level IV, and 8 (4%) Level V. One hundred forty-three studies (71%) were retrospective in nature. Stratification by study design revealed 128 (64%) case series, 33 (16%) experimental cohort studies, 19 (10%) case-control studies, 13 (6%) observational cohort studies, and 8 (4%) case reports. The number of studies published each year steadily increased from 2006 to 2016. A total of 51% of TAA research was published in only two journals: Foot and Ankle International and the Journal of Bone and Joint Surgery. Publications from the United States accounted for 36% of total publications. The most published implant was the Scandinavian Total Ankle Replacement (Figure 1). Conclusion: While the number of TAA studies published each year has steadily increased since 2006, the quality of this research as measured by level of evidence remains suboptimal. This analysis highlights the need for continued improvement in methodology and development of robust prospective registries to advance our knowledge of TAA as a treatment for end-stage ankle arthritis.

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Clinical Outcomes of Total Ankle Arthroplasty With Total Talar Prosthesis

Foot & Ankle International ◽

10.1177/1071100719847135 ◽

2019 ◽

Vol 40 (8) ◽

pp. 948-954

Author(s):

Noriyuki Kanzaki ◽

Nobuaki Chinzei ◽

Tetsuya Yamamoto ◽

Takahiro Yamashita ◽

Kazuyuki Ibaraki ◽

...

Keyword(s):

Range Of Motion ◽

Case Series ◽

Total Ankle Arthroplasty ◽

Medial Malleolus ◽

Level Of Evidence ◽

Ankle Arthroplasty ◽

The Mean ◽

End Stage ◽

Medial Malleolus Fracture

Background: Total ankle arthroplasty (TAA) has been developed to treat patients with end-stage ankle osteoarthritis (OA). However, there is often difficulty in treating complicated pathologies such as ankle OA with subtalar joint OA and severe talar collapse. Therefore, this study aimed to explore the short-term results and complications of TAA with total talar prosthesis, known as combined TAA, as the new techniques to treat such complicated pathology. Methods: We examined postoperative results including ankle range of motion, Japanese Society for Surgery of the Foot (JSSF) scale, and complications. There were 22 patients (15 women), with mean follow-up of 34.9 (range, 24–53 months), and the mean age was 72 (range, 62–80) years. The main indications for combined TAA included osteoarthritis (18 patients), rheumatoid arthritis (3 patients), and talar osteonecrosis with osteoarthritis (one patient). Results: The mean range of motion improved from 4.0 to 14.4 degrees in dorsiflexion and from 23.8 to 32.0 degrees in plantarflexion. The JSSF scale improved from 50.5 to 91.5 points. Prolonged wound healing occurred in 3 patients, and medial malleolus fracture occurred in 4 patients. Conclusion: Combined TAA was a reliable procedure for the treatment of not only ankle OA following avascular necrosis of talus but also of degeneration of both ankle and subtalar joints. Level of Evidence: Level IV, case series.

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Does Patient-specific Instrumentation Have a Higher Rate of Early Osteolysis than Standard Referencing Techniques in Total Ankle Arthroplasty?

Foot & Ankle Orthopaedics ◽

10.1177/2473011418s00047 ◽

2018 ◽

Vol 3 (3) ◽

pp. 2473011418S0004 ◽

Cited By ~ 1

Author(s):

Mario Escudero ◽

Kevin Wing ◽

Thomas Bemenderfer ◽

Michael Symes ◽

Maximiliano Barahona ◽

...

Keyword(s):

Soft Tissue ◽

Outcome Data ◽

Total Ankle Arthroplasty ◽

Treatment Modalities ◽

Patient Specific ◽

Fisher Exact Test ◽

Ankle Arthroplasty ◽

Patient Specific Instrumentation ◽

Soft Tissue Dissection ◽

Low Profile

Category: Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty (TAA) and ankle arthrodesis (AA) have been standard treatment modalities for end-stage ankle osteoarthritis. Final implant position and successful soft tissue balancing are key components to the longevity of total ankle implants. Patient-specific instrumentation (PSI) has been developed for TAA, with proven cost effectiveness, accurate and reproducible radiographic outcomes and less operative time. However, one concern regarding PSI is the need for more soft tissue dissection in order to accurately position the PSI guides, which has the theoretical disadvantage of increased localized adjacent tissue necrosis that may lead to early osteolysis. As such the purpose of our study is to compare the incidence and magnitude of osteolysis for a low-profile tibia and talar resurfacing implant between PSI and standard referencing (SR) techniques. Methods: The first 67 consecutive patients who underwent primary Infinity total ankle arthroplasty (TAA) at 2 North American sites between 2013 and 2015 were reviewed in a prospective observational study. Demographic, radiographic, and functional outcome data was collected preoperatively, at 6-12 months postoperatively, and annually thereafter. Osteolysis was assessed at two years after TAA, dividing the ankle into eight zones, and then a number was assigned according to lucency magnitude (see Figure) Osteolysis incidence was calculated by a binomial distribution. The number of zones compromised and magnitude of osteolysis was calculated using the median as resume statistic and interquartile range as dispersion statistic. Fisher exact test was used to compare osteolysis presence between groups; then a regression model was estimated to calculate the odds ratio for osteolysis. The comparison of osteolysis magnitude between groups was done with the Chi-squared test. A significance of 5% was used. Results: Of a total of 67 TAAs included, 51 were in the PSI group and 16 in the SRI group. In the PSI group the incidence, the number of compromised zones (CZ) and magnitude was 0.42% (0.25-0.61%), 3 [2-4] and 2[2-4] respectively. In the SR group, the incidence, number of CZ and magnitude was0.36% (0.13-0.65%), 2 [2-2], 4 [2-4] respectively. These differences were not statistically significant (p=0.46, p=0.86, p=0.70). A slightly higher risk of osteolysis was found in the PSI Groups (OR=1.33 [0.36- 4.83]). This difference was not statistically significant (p=0.46). Conclusion: According to our data, PSI is not different to SR in terms of risk, incidence and magnitude of early osteolysis in a low-profile tibia and talar resurfacing implant. We acknowledge that osteolysis is a multifactorial pathology, but these results suggest that the use of PSI does not increase its early occurrence. It appears that the higher rate of soft tissue stripping in the PSI group does not affect osteolysis and implant survival in the short term.

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Does Patient-specific Instrumentation Yield Better Component Position than Standard Instrumentation in Total Ankle Arthroplasty?

Foot & Ankle Orthopaedics ◽

10.1177/2473011418s00046 ◽

2018 ◽

Vol 3 (3) ◽

pp. 2473011418S0004

Author(s):

Mario Escudero ◽

Kevin Wing ◽

Feras Waly ◽

Thomas Bemenderfer ◽

W. Hodges Davis ◽

...

Keyword(s):

Computer Navigation ◽

Outcome Data ◽

Total Ankle Arthroplasty ◽

Patient Specific ◽

Published Data ◽

Time Efficiency ◽

Ankle Arthroplasty ◽

Radiographic Outcomes ◽

Patient Specific Instrumentation ◽

Standard Instrumentation

Category: Ankle Arthritis Introduction/Purpose: The unique anatomy and biomechanics of the ankle joint have made total ankle arthroplasty (TAA) challenging over the past few decades. Final implant position and successful soft tissue balancing are key components to the longevity of total ankle implants. Preoperative computer navigation, templating, and patient-specific instrumentation (PSI) have shown promising results in total ankle replacement with accurate and reproducible radiographic outcomes. Recent data has also suggested that even experienced surgeons benefit from the improved time efficiency of PSI. The purpose of this study is to determine if radiographic outcomes differ between patients undergoing TAA with PSI and those who undergo TAA with standard instrumentation (SI). Methods: The first 67 consecutive patients who underwent primary Infinity total ankle arthroplasty (TAA) at 2 North American sites between 2013 and 2015 were reviewed in a prospective observational study. All TAA’s were performed by one of four fellowship-trained foot and ankle surgeons. Demographic, radiographic, and functional outcome data was collected preoperatively, at 6-12 months postoperatively, and annually thereafter. The radiographic variables measured were the medial distal tibial angle (MDTA), talar tilt angle (TTA), lateral talar station (LTS), sagittal distal tibial articular angle (sDTAA), and the gamma angle. Acceptable intervals for each parameter were selected and TAAs were then categorized as being “correctly aligned” or “not correctly aligned” for all the parameters described. The rate of “correctly aligned” TAA’s was compared between cases with PSI and those with SI. Fisher’s exact test was used to analyze difference by groups. A significance of 5% was used. Results: Of a total of 67 TAAs included, 51 were in the PSI group and 16 in the SI group. No significant statistically differences were found between PSI and NPSI regarding MDTA (p=0.174), LTS (p=0.922), sDTAA (p=0.986), gamma angle (p=0.252) and TTA (p=0.145). We did not find a significant statistical difference in the rate of “correctly aligned TAR” when we compared both groups (p=0.35). Conclusion: This study suggests that both PSI and SI provide accurate and reproducible TAA radiographic alignment when performed by experienced surgeons. In view of previously published data demonstrating high levels of reproducibility for PSI in TAA, these data also suggest that PSI may offer a means for less experienced surgeons to achieve radiographic results similar to those achieved by experienced surgeons. It also suggests that experienced surgeons may not need to use PSI to achieve satisfactory implant alignment, though improved time efficiency with PSI, as demonstrated in other studies, may still be of benefit for experienced surgeons.

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Midterm Survivorship of the INBONE II Total Ankle Arthroplasty

Foot & Ankle International ◽

10.1177/10711007211060047 ◽

2021 ◽

pp. 107110072110600

Author(s):

Oliver J. Gagne ◽

Jonathan Day ◽

Jaeyoung Kim ◽

Kristin Caolo ◽

Martin J. O’Malley ◽

...

Keyword(s):

Survival Data ◽

Case Series ◽

Cyst Formation ◽

Total Ankle Arthroplasty ◽

Level Of Evidence ◽

Term Survival ◽

Metallic Component ◽

Ankle Arthroplasty ◽

Patient Reported

Background: The use of total ankle arthroplasty (TAA) in the treatment of ankle arthritis has grown substantially as advancements are made in design and surgical technique. Among the criteria guiding the choice between arthroplasty and arthrodesis, the long-term survival and postoperative outcomes are of crucial importance. Although outcomes of the INBONE I have been published, there is limited midterm survival data for the INBONE II. The purpose of this study was to determine the radiographic and patient-reported outcomes, and survivorship of this prosthesis in patients with a minimum 5-year follow-up. Methods: We retrospectively identified 51 ankles (46 patients) from 2010 to 2015 who underwent TAA with the INBONE II prosthesis at our institution. Of these, 44 cases had minimum clinical follow-up of 5 years (mean, 6.4; range 5-9). Median age was 66 years (range 42-81) and median BMI was 27.5 (range 20.1-33.0). A chart review was performed to record the incidence of revision and reoperation. Preoperative and postoperative radiographs were analyzed to assess the coronal tibiotalar alignment (TTA), the talar inclination angle, and the presence of periprosthetic lucencies and cyst formation. Preoperative and minimum 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscales were compared. Survivorship was determined by incidence of revision, defined as removal of a metallic component. Results: The survivorship at 5 years was 98% and the rate of reoperation was 7.8% (n = 4); 2 patients underwent irrigation and debridement for infection, 1 patient underwent a medializing calcaneal osteotomy, and 1 patient underwent open gutter debridement, 1 patient underwent a revision of a subsided talar component at 3.2 years after index surgery. Average postoperative TTA was 88.6 degrees, with 42 rated as neutral (85-95 degrees), 2 varus (<85 degrees), and no valgus (>95 degrees) ankles. At final follow-up, asymptomatic periprosthetic cysts were observed in 8 patients. All FAOS domain scores improved between preoperative and final follow-up. Conclusion: At midterm follow-up, we observed significant improvement in radiographic alignment and patient-reported outcome scores for the INBONE II total ankle prosthesis. In addition, this cohort has had a relatively low reoperation rate and high survivorship. Level of Evidence: Level IV, case series.

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