scholarly journals Accuracy of Weightbearing CT Scans for Patient-Specific Instrumentation in Total Ankle Arthroplasty

2021 ◽  
Vol 6 (4) ◽  
pp. 247301142110614
Author(s):  
Mitchell J. Thompson ◽  
Devon Consul ◽  
Benjamin D. Umbel ◽  
Gregory C. Berlet
Keyword(s):  
Total Ankle Arthroplasty ◽  
Patient Specific ◽  
Posttraumatic Arthritis ◽  
Inclusion Criteria ◽  
Ankle Arthritis ◽  
Initial Report ◽  
Ankle Arthroplasty ◽  
Component Size ◽  
Patient Specific Instrumentation ◽  
Preoperative Patient

Background: Total ankle arthroplasty (TAA) is a popular and viable option for end-stage ankle arthritis. Posttraumatic arthritis is the most common etiology of ankle arthritis, which creates the additional challenge of osseus deformity. Accuracy and reproducibility in placing the implant on the mechanical axis has been shown to be paramount in all joint arthroplasty including total ankle replacement. Patient-specific preoperative navigation is a relatively new technology for TAA, and up until this past year has been based off of nonweightbearing (NWBCT) or simulated weightbearing computed tomography (WBCT). Our institution has created a protocol to use WBCT in the preoperative patient-specific navigation for TAA using the Prophecy system. The purpose of our study was to compare the accuracy and reproducibility of implant alignment and size using WBCT vs prior studies using NWBCT for the Prophecy reports. Methods: All patients from July 2019 through October 2020 who underwent TAA were evaluated. Inclusion criteria consisted of primary TAA using patient-specific preoperative navigation who had postoperative radiographs in the 4-6-week time frame. Prophecy predictions and measurements were then compared to actual implant placement and size. Results: Ten patients met our inclusion criteria of WBCT Prophecy preoperative planning using 2 different implant systems. Preoperative deformities in this cohort were small. The average postoperative coronal alignment was 0.84 degrees, range 0.19 to 2.4 degrees. Average postoperative sagittal plane deformity was 1.9 degrees, range 0.33 to 5.05 degrees. Tibial component size was properly predicted in all patients, talar component in 9 of 10. Conclusion: This initial report supports accuracy and reproducibility in preoperative patient-specific navigation when using WBCT for TAA with these implants. All TAAs were within the intended target of less than 5 degrees varus or valgus. Level of Evidence: Level III, retrospective comparative analysis.

scholarly journals Accuracy and Reproducibility of a Patient-Specific Instrumentation in Total Ankle Arthroplasty

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0010
Author(s):  
Pierre-Marc April ◽  
Philippe Hugo Champagne ◽  
Magalie Angers ◽  
Karl-Andre R. Lalonde ◽  
Brad Meulenkamp ◽  
...  
Keyword(s):  
Tibial Component ◽  
Total Ankle Arthroplasty ◽  
Patient Specific ◽  
Foot And Ankle ◽  
Ankle Arthritis ◽  
Ankle Arthroplasty ◽  
Component Size ◽  
Patient Specific Instrumentation ◽  
Operation Rate ◽  
Accuracy Of Prediction

Category: Ankle Arthritis Introduction/Purpose: Ankle arthritis (OA) is a frequent and debilitating disease with the two primary surgical options being ankle arthrodesis or total ankle arthroplasty (TAA). TAA has the advantages maintenance of range of motion (ROM), a more normalized gait and potentially improved functional outcome over arthrodesis. Malaligned protheses have been demonstrated to have increased peak component pressures, potentially leading to component loosening, failure and overall worse outcomes. One TAA system uses pre-op CT to build patient-specific surgical instrumentation, with purported benefit of more reliable and accurate component positioning. The goal of this study is to evaluate reproducibility and accuracy of this system by surgeons without affiliation with the prosthesis design team. Methods: A retrospective radiological study was performed including two centers with four fellowship-trained foot and ankle surgeons using the patient-specific TAA system. All patients operated on between 2015-2018 were included. The primary outcome was alignment of the tibial implant in coronal and sagittal orientation relative to the tibia anatomic axis. All measurements were performed in duplicate an orthopaedic foot and ankle fellow and a musculoskeletal fellowship-trained radiologist. Secondary outcomes included accuracy of prediction of tibial and talar component size implanted compared to the engineered pre-operative plan, rate of prosthesis revision (at least one component) and overall re-operation rate. Results: 79 patients were included in the final review. The mean absolute deviation of the tibial component from tibial anatomical axis was 1.31° +/- 1.14in the coronal plane and 2.68°+/- 1.74 in sagittal alignment. 94.7 % of the implants were implanted within 3°of varus or valgus and 73.7% within 3°of dorsiflexion or plantiflexion. 86 % of the implanted tibial component were of the size predicted by the pre-op plan whereas it was found to be the case in 63 % of the talar component.At a mean follow-up of 22 months(3-52), two TAA (2.5%) have been revised due to aseptic tibial implant loosening. Conclusion: The patient-specific guide has been found to be a reliable system for coronal tibial implant alignment but less in the sagittal plane in the hand of surgeons not involved in the design of any TAA system. Accuracy of prediction of the tibial component size is high, moderate on the talar side. In this series there was a low rate of early component revision (2.5 %).

scholarly journals Mechanical and Anatomical Axis in Total Ankle Arthroplasty

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.

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

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0004 ◽  
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.

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

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.

scholarly journals Total Ankle Arthroplasty: Is Ankle Plantarflexion Strength Important?

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0002
Author(s):  
Frank E. DiLiberto ◽  
Steven L. Haddad ◽  
Daniel H. Aslan ◽  
Anand M. Vora
Keyword(s):  
Soft Tissue ◽  
Gait Speed ◽  
Total Ankle Arthroplasty ◽  
Joint Torque ◽  
Patient Specific ◽  
Control Group ◽  
Ankle Arthritis ◽  
Ankle Arthroplasty ◽  
Ankle Strength ◽  
End Stage

Category: Ankle Arthritis Introduction/Purpose: Ankle push off power, which requires gastroc-soleus muscle strength, is a critical aspect of healthy gait and increases as gait speed increases. It is therefore surprising that one-to-two-year outcomes following total ankle arthroplasty (TAA) include improved gait speed but deficient ankle power. One possible explanation for low ankle power following TAA is ankle plantarflexion weakness. Information on plantarflexion strength is extremely limited in people before or after TAA. Evaluating plantarflexion strength may inform postoperative expectations and guide rehabilitation programs. The purpose of this study was to evaluate the change in ankle plantarflexion strength, ankle power during gait, and gait speed before and after TAA in people with end-stage ankle arthritis, and in comparison to a healthy matched control group. Methods: Twenty-five participants were included in this prospective case-control study. TAA group participants (n = 13) [mean (SD): Age 60.9 (15.3) years; BMI 30.53 (5.5) Kg/m2; 85% male] with end-stage ankle arthritis who received a TAA were evaluated preoperatively and six months postoperatively. Performance of adjunct soft tissue procedures were patient specific (5/13 participants received tendo-achilles lengthening). All patients received formal physical therapy. Healthy control participants (n=12) were matched to the TAA group on age, gender and BMI. Ankle peak isokinetic plantarflexion strength (torque at 60 and 120 degrees/second; Nm/kg) was measured with an instrumented dynamometer. Peak ankle power (joint torque x segmental velocity; W/kg) was calculated via three-dimensional multi-segment foot motion analysis while participants walked barefoot over a force plate at controlled speeds. Gait speed (m/s) was measured with the Six-Minute Walk Test. Appropriate nonparametric comparisons were made to evaluate differences across time, between limbs, and between groups. Results: Compared to preoperative values, involved limb ankle strength was preserved at 60 and 120 degrees/second following TAA (both p > 0.59). Postoperative involved limb ankle strength at both speeds were 37-56% lower than the non-involved limb and control group (all p < 0.05) (Figure 1). Similarly, involved limb ankle power was preserved following TAA (p = 0.43), but remained at least 38% lower than the non-involved limb or control group (both p < .01). A subset analysis revealed that TAA participants with tendo-achilles lengthening had 25-33% less involved limb postoperative ankle power and strength than TAA participants without tendo-achilles lengthening. Interestingly, gait speed increased following TAA (p = 0.01) and was similar to control group speeds [TAA 1.5 vs. Control 1.6 m/s; p = 0.59]. Conclusion: Robust improvements in gait speed were observed following TAA. These values approached normative gait speed in spite of diminished ankle strength and power. Ankle plantarflexion weakness reduces the capacity to generate ankle power during gait, regardless of possible contributing factors (i.e. preexisting atrophy/weakness, tendo-achilles lengthening). Accordingly, improvements in gait speed were likely linked to proximal joint compensations (i.e. hip, knee). The long term consequences of plantarflexion weakness may negatively affect implant loading. Study findings provide new information and point to the importance of targeting strength during postoperative TAA rehabilitation, potentially adjusting strategies for patients receiving soft tissue lengthening procedures.

Accuracy and Reproducibility Using Patient-Specific Instrumentation in Total Ankle Arthroplasty

2016 ◽  
Vol 38 (4) ◽  
pp. 412-418 ◽  
Author(s):  
Justin Daigre ◽  
Gregory Berlet ◽  
Bryan Van Dyke ◽  
Kyle S. Peterson ◽  
Robert Santrock
Keyword(s):  
Total Ankle Arthroplasty ◽  
Patient Specific ◽  
Ankle Arthroplasty ◽  
Patient Specific Instrumentation

Total Ankle Arthroplasty Radiographic Alignment Comparison Between Patient-Specific Instrumentation and Standard Instrumentation

2021 ◽  
pp. 107110072199637
Author(s):  
Mario I. Escudero ◽  
Vu Le ◽  
Thomas Bradford Bemenderfer ◽  
Maximiliano Barahona ◽  
Robert B. Anderson ◽  
...  
Keyword(s):  
Sagittal Alignment ◽  
Distal Tibia ◽  
Total Ankle Arthroplasty ◽  
Patient Specific ◽  
Fisher Exact Test ◽  
Exact Test ◽  
Ankle Arthroplasty ◽  
Patient Specific Instrumentation ◽  
Standard Instrumentation ◽  
Radiographic Alignment

Background Several benefits are published supporting patient-specific instrumentation (PSI) in total ankle arthroplasty (TAA). This study seeks to determine if TAA with PSI yields different radiographic outcomes vs standard instrumentation (SI). Methods: Sixty-seven primary TAA patients having surgery using PSI or SI between 2013 and 2015 were retrospectively reviewed using weightbearing radiographs at 6-12 weeks postsurgery. Radiographic parameters analyzed were the medial distal tibia angle (MDTA), talar-tilt angle (TTA), anatomic sagittal distal tibia angle (aSDTA), lateral talar station (LTS), and talar component inclination angle (TCI). A comparison of the 2 groups for each radiologic parameter’s distribution was performed using a nonparametric median test and Fisher exact test. Furthermore, TAAs with all radiographic measurements within acceptable limits were classified as “perfectly aligned.” The rate of “perfectly aligned” TAAs between groups was compared using a Fisher exact test with a significance of .05. Results: Of the 67 TAAs, 51 were done with PSI and 16 with SI. There were no differences between groups in MDTA ( P = .174), TTA ( P = .145), aSDTA ( P = .98), LTS ( P = .922), or TCI angle ( P = .98). When the rate of “perfectly aligned TAA” between the 2 groups were compared, there was no significant difference ( P = .35). Conclusion: No significant radiographic alignment differences were found between PSI and SI implants. This study showed that both techniques achieve reproducible TAA radiographic coronal and sagittal alignment for the tibial component when performed by experienced surgeons. The talar component’s sagittal alignment is similar whether or not PSI was used but is noticeably different from normal anatomic alignment by design. Level of Evidence: Level III, retrospective cohort study using prospectively collected data.

Use of CT Scan-derived Patient-specific Instrumentation in Total Ankle Arthroplasty

2017 ◽  
Vol 16 (4) ◽  
pp. 183-189
Author(s):  
Guilherme H. Saito ◽  
Austin E. Sanders ◽  
Daniel R. Sturnick ◽  
Constantine A. Demetracopoulos
Keyword(s):  
Ct Scan ◽  
Total Ankle Arthroplasty ◽  
Patient Specific ◽  
Ankle Arthroplasty ◽  
Patient Specific Instrumentation

scholarly journals Total Ankle Arthroplasty Results Using Fixed Bearing CT-Guided Implants in Post-Traumatic Versus Non-Traumatic Arthritis

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0009
Author(s):  
Assaf Albagli ◽  
Susan M. Ge ◽  
Patrick Park ◽  
Dan Cohen ◽  
E. Ruth Chaytor ◽  
...  
Keyword(s):  
Total Ankle Arthroplasty ◽  
Patient Specific ◽  
Foot And Ankle ◽  
Fixed Bearing ◽  
Ankle Arthritis ◽  
Ankle Osteoarthritis ◽  
Ankle Arthroplasty ◽  
Traumatic Group ◽  
Post Traumatic

Category: Ankle; Ankle Arthritis; Trauma Introduction/Purpose: The majority of ankle osteoarthritis are post-traumatic in etiology. Previous studies have shown that patients with post-traumatic ankle osteoarthritis are less satisfied, experience significantly more pain during normal activities and have higher revision rates. However, these studies were performed with older generation implants. The objective of this study was to compare patients hat had undergone total ankle arthroplasty secondary to either post-traumatic or non-traumatic etiologies using patient specific, third generation fixed bearing implants and compare clinical as well as radiographic outcomes. Methods: A retrospective chart review was conducted on 41 patients who had undergone total ankle arthroplasty using a third- generation fixed bearing implant with CT-based patient specific cutting guides from July 21, 2015 to December 13, 2017 performed by 2 foot and ankle surgeons. Demographic and operative data was collected. Etiology was determined based on clinical notes, operative notes, and x-rays. Clinical outcomes were obtained using the Foot and Ankle Ability Measure questionnaire. Radiographic assessment of the coronal and sagittal alignments were carried out to assess implant migration or loosening. Results: We had 26 patients in the post-traumatic group and 15 in the non-traumatic group with a mean follow-up of 32.5 months and 30.4 months respectively. There was no significant difference between both groups in terms of FAAM ADL subscore with the post-traumatic group did slightly better with 7 patients scoring ‘nearly normal’ (26.9%) and 18 patients scoring ‘normal’ (69.2%). Whereas in the non-traumatic group 5 patients score ‘nearly normal’ (33.3%) and 9 patients score ‘normal’ (60%). In terms of the self-rated subjective functioning score, mean score of 79.2% and 73.4% respectively. On radiographs, there was no subsidence or significant implant movement for both groups at mean follow-up of 28.3 months for the post-traumatic group and 26.3 months for the non-traumatic group. Conclusion: Unlike in previous studies in older implants where clinical outcomes were worse in post-traumatic ankle arthritis, our study showed that those receiving total ankle arthroplasty due to post traumatic osteoarthritis do slightly better than those with non-traumatic osteoarthritis, with more patients reporting normal levels of activity. These results may help quantify improvements in newer generation patient specific implants as well as to gain insight into how different implant designs affect post- operative outcomes based on etiology of ankle osteoarthritis.

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