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.

Does Patient-Specific Instrumentation Have a Higher Rate of Early Osteolysis Than Standard Referencing Techniques in Total Ankle Arthroplasty? A Radiographic Analysis

2019 ◽  
Vol 13 (1) ◽  
pp. 32-42
Author(s):  
Mario I. Escudero ◽  
Michael Symes ◽  
Thomas Bradford Bemenderfer ◽  
Maximiliano Barahona ◽  
Robert Anderson ◽  
...  
Keyword(s):  
Odds Ratio ◽  
Total Ankle Arthroplasty ◽  
Patient Specific ◽  
Fisher Exact Test ◽  
Therapeutic Level ◽  
Exact Test ◽  
Ankle Arthroplasty ◽  
Patient Specific Instrumentation ◽  
Soft Tissue Dissection ◽  
Significant Difference

Introduction: Patient-specific instrumentation (PSI) has been developed for total ankle arthroplasty (TAA), with proven benefits. 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 osteolysis. The purpose of our study is to compare the incidence and magnitude of osteolysis for the INFINITY Total Ankle System between PSI and standard referencing (SR) techniques. Methods: Sixty-seven patients who underwent primary TAA using Prophecy (PSI) or SR technique between 2013 and 2015 were reviewed in a retrospective observational study. Osteolysis was assessed on radiographs at 2 years. The incidence was calculated by binomial distribution. The number of zones compromised and the magnitude of osteolysis was calculated using the median as a summary statistic and interquartile range as dispersion statistic. Fisher exact test was used to compare both groups, then a regression model was estimated to calculate the odds ratio for osteolysis. Results: Of the 67 TAAs, 51 were in the PSI group and 16 in the SR group. In the PSI group the incidence, number of compromised zones (CZ), and magnitude was 41% (25%-59%), 1 [1-2], and 2 [2-3], respectively. In the SR group these were 36% (13%-65%), 3 [2-3], and 3 [2-4], respectively. No significant differences were found ( P = .46, P = .12, P = .33). A slightly higher risk of osteolysis was found in the PSI group (odds ratio = 1.33 [0.36-4.83]) ( P = .46). The majority of lesions were in 1 zone with size of 2 to 5 mm (63% for all cohort, 64% PSI, 60% SR). Two cases underwent revision for aseptic loosening, 1 in the SR group and 1 in the PSI group. Conclusion: According to our data, there is no significant difference between PSI and SR in terms of risk, incidence, size and magnitude of osteolysis in the INFINITY Total Ankle System at 2 years. Levels of Evidence: Therapeutic, Level III, Retrospective cohort study

Mechanical and anatomical axis of the lower limb in total ankle arthroplasty

The Foot ◽  
2020 ◽  
Vol 44 ◽  
pp. 101666
Author(s):  
Ali-Asgar Najefi ◽  
Karan Malhotra ◽  
Andy Goldberg
Keyword(s):  
Lower Limb ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthroplasty ◽  
Anatomical Axis

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 Accuracy of Coronal Plane Mechanical Alignment in a Customized, Individually Made Total Knee Replacement with Patient-Specific Instrumentation

2017 ◽  
Vol 31 (08) ◽  
pp. 792-796 ◽  
Author(s):  
Gary Levengood ◽  
Jack Dupee
Keyword(s):  
Mechanical Axis ◽  
Computer Assisted Surgery ◽  
Coronal Plane ◽  
Patient Specific ◽  
Computer Assisted ◽  
Consecutive Series ◽  
Mechanical Alignment ◽  
Patient Specific Instrumentation ◽  
Patient Specific Instruments ◽  
Total Knee

AbstractThe objective of this study was to evaluate the accuracy of a customized individually made total knee implant used in conjunction with patient-specific cutting guides in restoring coronal plane mechanical axis alignment using computer-assisted surgery (CAS). A consecutive series of 63 total knee arthroplasty (TKA) patients were prospectively measured with intraoperative CAS. The patient-specific instruments and implants were created utilizing a preoperative CT scan. CAS system was used for all patients, to determine mechanical alignment. Bone cuts were made using the patient-specific instruments. Both bone cuts and final coronal mechanical alignment were recorded utilizing the navigation system for the assessment.The patient-specific instruments and implants provided perfect neutral coronal mechanical alignment (0°) in 53 patients. The remaining 10 patients had a postoperative alignment within ± 2° of neutral. The average preoperative deformity was 5.57° versus 0.18° postoperatively (p < 0.0001). The mean correction angle was 5.68°. No patients had postoperative extension deficits as measured with CAS (7.50° pre-op for 40/63 patients). Customized, individually made total knee implant with patient-specific cutting jigs showed results that are comparable to those of CAS systems in this study. This technology restores the neutral coronal mechanical axis very accurately, while offering unique benefits such as improved implant fit and restoration of the patient's J-curves, which require further investigation.

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

scholarly journals Mid-Term (4-10 year) Outcomes of INBONE I Total Ankle Arthroplasty with Deformity Analysis

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0001
Author(s):  
Andrew Harston ◽  
James Nunley ◽  
Mark Easley ◽  
James DeOrio ◽  
Samuel Adams ◽  
...  
Keyword(s):  
Short Form ◽  
Total Ankle Arthroplasty ◽  
Coronal Plane ◽  
Consecutive Series ◽  
Ankle Arthroplasty ◽  
Sf 36 ◽  
Significant Difference ◽  
Patient Reported ◽  
Plane Deformity

Category: Ankle, Ankle Arthritis Introduction/Purpose: Concerns for limited coronal plane stability prompted the manufacturer and designers of the INBONE total ankle arthroplasty system to replace the original saddle-shaped talar component (INBONE I) with a sulcus-shaped talar component (INBONE II). Prior to the availability of the INBONE II talar component, numerous INBONE I total ankle replacements were performed. To our knowledge mid-term outcomes of INBONE I total ankle arthroplasty have not been reported. This study compares the mid-term outcomes of patients with and without preoperative coronal plane deformity who underwent total ankle replacement with the INBONE I prosthesis. In our opinion, the longer-term outcomes of the INBONE I prosthesis are important for patient and surgeon education. Methods: A consecutive series of patients, from May, 2007 to September, 2011, at a single institution who underwent total ankle arthroplasty with the INBONE I Total Ankle Arthroplasty (Wright Medical) were prospectively enrolled. Pain and patient- reported function were assessed preoperatively and at yearly follow-ups with use of a visual analog scale (VAS) for pain, the American Orthopaedic Foot & Ankle Society (AOFAS) ankle- hindfoot score, the Short Musculoskeletal Function Assessment (SMFA), and the Short Form-36 (SF-36) Health Survey. We analyzed the data for complications, reoperations, and failures (defined as undergoing revision for exchange or removal of the metallic components for any reason). Patients were grouped according to coronal plane tibiotalar alignment (preoperative coronal plane malalignment of >10 degrees and <10 degrees deformity) and outcomes compared. Results: One-hundred fifty-five INBONE I prostheses were implanted in 151 patients, with minimum 4 year clinical and radiographic follow-up. Follow-up ranged from 48-113 months with an average of 67 months. There was significant (p<0.05) improvement in the VAS, AOFAS, SMFA, and SF-36 scores at most recent follow-up. Forty-five patients (29%) had 49 additional surgeries for impingement, loosening/subsidence, malalignment, ligament instability, polyethylene exchange, and/or infection. There were 14 implant failures with overall survivorship of 90.3%. There was no statistically significant difference in outcomes between patients with coronal plane deformity >10 degrees (47.7%) and <10 degrees (52.3%). Patients with >10 degrees had fewer reoperations (19 vs. 30) and fewer revisions (5 vs. 9) when compared to patients with <10 degrees deformity. Conclusion: Patients who underwent INBONE I total ankle arthroplasty demonstrated significant improvement in pain and patient-reported outcomes at a mean of 5.7 years post-operatively. The patients with preoperative coronal plane tibiotalar deformity had similar pain relief, function, and need for additional surgeries and revisions. Despite the presumed shortcomings of the INBONE I’s saddle-shaped talar design, this operation shows promising results, with or without deformity, at mid-term follow- up with survivorship of 90.3%.

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.

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.

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