scholarly journals Functional Outcome Risk Score for Total Ankle Arthroplasty

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0008
Author(s):  
Elizabeth McDonald ◽  
Kristen Nicholson ◽  
Max Greenky ◽  
Benjamin Hendy ◽  
Abhay Mathur ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Functional Outcome ◽  
Risk Score ◽  
Functional Outcomes ◽  
Ligament Reconstruction ◽  
Total Ankle Arthroplasty ◽  
Coronal Plane ◽  
Ankle Arthroplasty ◽  
Calculated Risk ◽  
Plane Deformity

Category: Ankle Introduction/Purpose: Postoperative functional outcomes are important measures as the orthopaedic community responds to pay-for-performance and bundled payments. Considering the 1000-fold growth of total ankle arthroplasty (TAA) procedures in the Medicare population in the past two decades, this procedure will likely undergo increasing scrutiny of quality under Medicare Access and Children’s Health Insurance Program Reauthorization Act of 2015(MACRA). While BMI, coronal plane deformity, age, and rheumatoid arthritis influence outcomes and rate of complications after TAA, there has been no single identifiable factor that predicts poor functional outcomes. The aim of this study is to identify independent patient factors that are associated with lower functional outcomes at two years after TAA and compound these predictive factors into an easily calculable score to preoperatively stratify patients undergoing modern TAA. Methods: 134 consecutive patients (136 ankles) with a mean age of 64 years (range, 31 to 79 years) and 70 (51%) men that had undergone TAA by a single surgeon from May 2011 to May 2015 were retrospectively enrolled. In addition to 2-year functional outcomes for each patient, 22 data point were collected including preoperative range of motion; baseline functional scores; and a comprehensive health history. FAAM ADL scores at 2-years were grouped into excellent (>90 points), good (75-90), or fair (<75). Univariable analyses tested for the association between demographics, medical history, functional outcomes, and procedure factors using chi-squared tests for categorical variables and either one-way ANOVAs or Kruskal Wallis tests for continuous variables. Model coefficients from a multivariable ordinal logistic regression analysis for the significant predictors of excellent, good, or fair outcomes were used to create a summed risk score to predict inferior 2-year outcome scores. Results: Ninety-one patients met the inclusion criteria. The only predictors associated with inferior functional outcomes were (1) baseline ADL score (2) no calcaneal osteotomy for coronal plane deformity (3) lateral or deltoid ligament reconstruction and (4) post-traumatic/chronic sprain etiology and BMI >30. From the multivariable ordinal logistic regression, baseline ADL scores less than 40 had a weight of 2 while an ADL score of 40-55 had a weight of 1. The remaining factors were weighted 3, 2, 1 for ligament reconstruction, no calcaneal osteotomy, and obese+sprain. Of the 23 patients with a calculated risk of 0-2, 18 did excellent and 2 did fair. Conversely, of the 22 patients with a calculated risk score of 4+, only 2 did excellent and 15 did fair (Table 1). Conclusion: Over twenty baseline and surgical factors were considered when creating a clinical scoring system that compounds the effect of risk factors on postoperative foot and ankle functional outcome measures at two years. Ligament reconstruction was the highest weighted factor(3-points), which suggests soft tissue stabilization needs to be considered in conjunction with boney correction. As previous literature supports, preoperative coronal plane deformity when corrected appropriately can lead to greater likelihood for superior outcomes when compared to patients without this deformity. This novel risk score takes into account 5 easily-obtainable factors and may help to better set patient expectations prior to TAA.

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%.

scholarly journals Heterotopic Ossification in Total Ankle Arthroplasty

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0002
Author(s):  
Thomas Bemenderfer ◽  
Robert Anderson ◽  
Mario Escudero ◽  
Feras Waly ◽  
Kevin Wing ◽  
...  
Keyword(s):  
Systematic Review ◽  
Range Of Motion ◽  
Functional Outcome ◽  
Heterotopic Ossification ◽  
Functional Outcomes ◽  
Total Ankle Arthroplasty ◽  
Minimal Clinical Important Difference ◽  
Ankle Arthroplasty ◽  
Wide Range

Category: Ankle Arthritis Introduction/Purpose: Heterotopic ossification (HO) following total ankle arthroplasty (TAA) is a known sequela and has been reported to contribute to reduced postoperative range of motion and poor patient functional outcomes. However, conflicting results have been reported in the literature with respect to the correlation between HO and clinical outcome. As new strategies and implants continue to be designed, it is important to understand what instruments for measuring the outcome of treatment are important to assess when evaluating outcome measures in TAA. The present study documents the incidence of HO and functional outcome for the novel 2 component fixed bearing Infinity Total Ankle System prosthesis at minimum of two year follow up and reports a systematic review of the literature. Methods: We reviewed the incidence, degree of severity, and functional outcome in 67 consecutive patients who underwent primary Infinity TAA at two North American tertiary medical centers between 2013 and 2015 in a prospective observational study. Radiographic and functional outcome data was collected preoperatively, at 6 to 12 months postoperatively, and annually thereafter. In addition, we conducted a systematic review of studies reporting the incidence of HO following TAA. We included peer-reviewed studies reporting on at least 20 TAAs with minimum follow up of two years. Results: While the incidence of HO was 68% at 2.4 years in the 67 patients who underwent primary Infinity TAA, there was no association between HO and AOFAS (HO 73.9, no HO 55.0), SF36-PCS (HO 50.1, no HO 45.2), FFI (HO 22.1, no HO 26.4), and VAS (HO 2.6, no HO 2.3). Fourteen studies with 1201 TAAs were included. The overall incidence of HO following TAA was approximately 56.6% at average 3.8 years with a wide range (range, 22.2-100%). Four studies (299 ankles) did not address functional outcomes. Nine studies (822 ankles) reported no association between functional outcomes and HO. One study (80 ankles) reported a statistically significant difference in range of motion of 7 degrees of dorsiflexion and a 7-point difference in AOFAS score. Conclusion: There was no association between HO and functional outcome in our observational cohort. Only one study demonstrated statistically significant differences in range of motion and functional outcome due to HO. Although the minimal clinical important difference in ankle dorsiflexion and AOFAS has not been established in TAA, these differences are below the minimal clinical important difference established in other foot and ankle procedures. Available data, including the results in our 67 patients, suggests that clinical function is independent of the presence of HO.

Analysis of the Effect of Tibial Stem Length on Coronal Plane Deformity of the Tibial Component in Total Ankle Arthroplasty

2019 ◽  
Vol 40 (10) ◽  
pp. 1166-1174 ◽  
Author(s):  
Gregory C. Berlet ◽  
Travis M. Langan ◽  
Marissa D. Jamieson ◽  
Allen M. Ferrucci
Keyword(s):  
Tibial Component ◽  
Case Series ◽  
Total Ankle Arthroplasty ◽  
Coronal Plane ◽  
Stem Length ◽  
Term Survival ◽  
Ankle Arthroplasty ◽  
Significant Difference ◽  
Plane Deformity ◽  
Stem Segments

Background:Coronal plane deformity is common in patients who undergo total ankle arthroplasty. The correction of this deformity is paramount to the long-term survival of the implant. Coronal plane correction is achieved with soft tissue balancing and, in some part, is maintained through articular geometry constraint. The purpose of this study was to assess the influence of tibial component stem length on the coronal plane stability.Methods:A consecutive case series of stemmed implants that met inclusion criteria were reviewed to determine the correction and maintenance of the correction of coronal plane deformity with special emphasis on the effect of modular tibial stem lengths of 2 and >2 segments. Twenty patients received a tibial component with 2 stem segments, and 23 patients received a tibial component with >2 stem segments. At an average patient age of 62.1 years at implantation, there was no significant difference between the 2 cohorts with respect to preoperative deformity or demographics.Results:Our case series had a mean coronal deformity of 5.7 degrees, with valgus being more common than varus. At a mean final radiographic follow-up of 266.3 days after the first postoperative weightbearing radiography, coronal deformity increased by 0.4 degrees ( P = .031). From the first postoperative measurement to the last postoperative measurement, there was no difference in mean coronal plane ankle deformity change between patients who received 2 stem segments and patients who received >2 stem segments ( t = −1.14, df = 41, P = .259).Conclusion:Coronal plane deformity had a tendency to recur, albeit at a much smaller angle than preoperatively. This recurrence of deformity did not occur because of tibial component movement. Tibial stem lengths of >2 segments did not influence the maintenance of correction of coronal plane deformity or the stability of the tibial component in the coronal plane.Level of Evidence:Level III, retrospective comparative series.

scholarly journals 5 Year Follow Up Evaluation of a Third Generation Fixed Bearing Total Ankle Arthroplasty with an Intramedullary Tibial Component and a Central Sulcus Talus

2020 ◽  
Vol 5 (2) ◽  
pp. 2473011420S0000
Author(s):  
Evan M. Loewy ◽  
Robert B. Anderson ◽  
Bruce E. Cohen ◽  
Carroll P. Jones ◽  
W. Hodges Davis
Keyword(s):  
Tibial Component ◽  
Total Ankle Arthroplasty ◽  
Coronal Plane ◽  
Third Generation ◽  
Fixed Bearing ◽  
Ankle Arthritis ◽  
Central Sulcus ◽  
Ankle Arthroplasty ◽  
Plane Deformity

Category: Ankle Arthritis, Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) has been shown to be a viable option in the treatment of end stage ankle arthritis (ESAA). Early reports demonstrated good results with intramedullary fixation implants. Third generation implants of this kind added a central sulcus to the talar component. This is a report of clinical follow up data from a prospectively collected database at a single US institution using a Third generation fixed bearing total ankle arthroplasty implant with a stemmed tibial component and a talar component with a central sulcus. To our knowledge, this is the first report of 5 year follow up data for this implant. Methods: Patients undergoing primary TAA at a single institution by one of four fellowship trained orthopedic foot and ankle surgeons with a Third generation fixed bearing implant consisting of an intramedullary stemmed tibial component and a sulcus talus that were at least 5 years postoperative were reviewed from a prospectively collected database. These patients were followed at regular intervals with history, physical examination and radiographs. All ankles were classified using the Canadian Orthopedic Foot and Ankle Society (COFAS) End-Stage Ankle Arthritis Classification System. The primary outcome was implant survivability. Secondary outcomes included pre- and postoperative coronal plane radiographic alignment, evaluation for osteolysis, and failure mode when applicable. All reoperation events were recorded using the COFAS Reoperations Coding System (CROCS). Results: 126 TAA with this implant were performed in 124 patients between 2010 and 2013; 74 met inclusion criteria for our study. The mean age at surgery was 61.6 +- 10.0 years (range 38.7-84.3). Four patients died with their initial implants in place. The mean duration of follow up for living patients that retained both initial components at final follow-up was 6.2 +- .9 years (range 4.7-8.1 years). 35% (26 of 74) of ankles had a preoperative coronal plane deformity of at least 10 degrees. 11% (8 of 74) of the ankles had a preoperative coronal plane deformity of at least 20 degrees. There were 6 (8%) implant failures that occurred at a mean 2.0 +- 1.4 years postoperative. Two failures were due to deep infection. One failure was related to talar component subsidence. All failures occurred in patients with =preoperative coronal plane deformity of less than 5 degrees. 81% (60 of 74) of TAA had no reoperation events in the follow up period. Conclusion: This cohort of TAA patients with minimum 5 year follow up using a third generation fixed bearing implant demonstrates acceptable implant survival, improved reoperation rates, and maintenance of coronal plane alignment. These data also suggest tolerance of a larger preoperative deformity with improved implant design. Continued follow up and reporting is needed to ensure that these favorable outcomes are maintained. Additionally, further investigation on acceptable coronal plane alignment correction with TAA is needed to determine the possible limitations of this procedure.

Should 15° of valgus coronal-plane deformity be the upper limit for a total ankle arthroplasty?

2020 ◽  
Vol 102-B (12) ◽  
pp. 1689-1696
Author(s):  
Mansur M. Halai ◽  
Ellie Pinsker ◽  
Matthew A. Mann ◽  
Timothy R. Daniels
Keyword(s):  
Short Form ◽  
Valgus Deformity ◽  
Total Ankle Arthroplasty ◽  
Coronal Plane ◽  
Ankle Arthroplasty ◽  
Sf 36 ◽  
Secondary Procedures ◽  
Plane Deformity ◽  
Short Form Health

Aims Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°. Methods A matched cohort of patients similar for demographics and components used but differing in preoperative coronal-plane tibiotalar valgus deformity ≥ 15° (valgus, n = 50; 52% male, mean age 65.8 years (SD 10.3), mean body mass index (BMI) 29.4 (SD 5.2)) or < 15° (control, n = 50; 58% male, mean age 65.6 years (SD 9.8), mean BMI 28.7 (SD 4.2)), underwent TAA by one surgeon. Preoperative and postoperative radiographs, Ankle Osteoarthritis Scale (AOS) pain and disability and 36-item Short Form Health Survey (SF-36) version 2 scores were collected prospectively. Ancillary procedures, secondary procedures, and complications were recorded. Results At mean 5.1 years follow-up (SD 2.6) (valgus) and 6.6 years (SD 3.3) (controls), mean AOS scores decreased and SF-36 scores increased significantly in both groups. Improvements in scores were similar for both groups – AOS pain: valgus, mean 26.2 points (SD 24.2), controls, mean 22.3 points (SD 26.4); AOS disability: valgus, mean 41.2 points (SD 25.6); controls, mean 34.6 points (SD 24.3); and SF-36 PCS: valgus, mean 9.1 points (SD 14.1), controls, mean 7.4 points (SD 9.8). Valgus ankles underwent more ancillary procedures during TAA (40 (80%) vs 13 (26%)) and more secondary procedures postoperatively (18 (36%) vs 7 (14%)) than controls. Tibiotalar deformity improved significantly (p < 0.001) towards a normal weightbearing axis in valgus ankles. Three valgus and four control ankles required subsequent fusion, including two for deep infections (one in each group). Conclusion Satisfactory mid-term results were achieved in patients with preoperative valgus malalignment ≥ 15°, but they required more adjunctive procedures during and after TAA. Valgus coronal-plane deformity ≥ 15° is not an absolute contraindication for TAA if associated deformities are addressed. Cite this article: Bone Joint J 2020;102-B(12):1689–1696.

The Impact of Concomitant Ipsilateral Knee Pain on Functional Outcomes in Total Ankle Arthroplasty

2020 ◽  
pp. 193864002095089
Author(s):  
Michael J. Symes ◽  
Alastair Younger ◽  
Mario Escudero ◽  
Murray J. Penner ◽  
Kevin Wing ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Knee Pain ◽  
Functional Outcomes ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthritis ◽  
Pain Group ◽  
Ankle Arthroplasty ◽  
End Stage ◽  
The Impact ◽  
Disease Specific

In end-stage ankle arthritis, little is known about the impact of concomitant knee pathology, including the impact of ipsilateral knee pain on total ankle arthroplasty (TAA) outcomes. The aim of this study was to determine the prevalence of ipsilateral preoperative knee pain in patients undergoing TAA and analyze its impact on patient-reported functional outcome measures (PROMs). A retrospective review was performed on the Vancouver End Stage Ankle Arthritis Database at a single institution. In total, 114 patients were studied, with patient demographics collected preoperatively, including the presence or absence of knee pain. Postoperative follow-up was performed at 5 years, primarily analyzing disease-specific PROMs, including the Ankle Osteoarthritis Score (AOS) and Ankle Arthritis Score (AAS). Multivariate mixed-effects linear regression models compared the scores between the groups. In total, 31 patients (27.2%) presented with concomitant ipsilateral knee pain. Despite more females in the knee pain group (64.5% vs 36.1%) there were no other significant differences at baseline between the knee pain and no knee pain groups in terms of demographics or baseline primary disease specific PROMs. At 5 years, the patients with knee pain had significantly worse AAS (37.9 ± 23.8 vs 21.2 ± 16.3, P = .004) and AOS total scores (38.1 ± 24.1 vs 21.9 ± 15.5, P = .005) compared with the no-knee pain group. Both groups improved significantly from baseline across all outcome measures; however, the magnitude of improvement was less in the knee pain group. Our study demonstrated that over one-quarter of patients with end-stage ankle arthritis undergoing TAA present with ipsilateral concomitant knee pain. If present, it is associated with worse functional outcomes at the 5-year mark. Further studies are needed to evaluate if knee pain influences complications, implant failure rates, and survival. Levels of Evidence: Level III

scholarly journals Arthroplasty or Arthrodesis in the CJR Era

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0024
Author(s):  
MaCalus Hogan ◽  
Monique Chambers ◽  
Joseph Kromka ◽  
Dwayne Carney ◽  
Alan Yan ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Joint Replacement ◽  
Functional Outcomes ◽  
Surgical Intervention ◽  
Quality Care ◽  
Total Ankle Arthroplasty ◽  
Ankle Arthritis ◽  
Ankle Arthroplasty ◽  
Insurance Type ◽  
The Impact

Category: Ankle Arthritis Introduction/Purpose: Ankle arthritis can be a debilitating disease that results in decreased daily activity and chronic morbidity. Many patients elect for surgical intervention to minimize pain and improve function. To curb costs associated with the increasing demand for total joint arthroplasty (TJA) in the growing elderly Medicare population, CMS announced the Comprehensive Care for Joint Replacement (CJR) model, which included total ankle arthroplasty. To provide continued quality care and cost containment, it is necessary to determine the optimal surgical intervention for patients that could fall within the CJR program. Therefore, we sought to determine the impact of surgical fixation on functional outcomes, systemic utilization, and medical expenditures for patients with ankle arthritis. Methods: We reviewed a prospectively collected and maintained database to identify all patients who underwent a total joint replacement from April 2016 to September 2017. Patients were identified based on DRG codes for primary arthritis of a lower extremity joint, then specifically for foot and ankle, as well as CPT codes for ankle arthroplasty (27702) or ankle arthrodesis (27870/28725). Functional outcomes were assessed based on insurance type. The cohorts were matched for age, comorbidities, and gender. Statistical analysis was performed using chi-squared and paired t-test to assess for differences in patient reported outcomes. Descriptive statistical analysis was used to assess for differences in cost between the cohorts. Results: A total of 573 patients were included.There were 48 replacements and 47 fusions. Arthrodesis procedures costs approximately $6,500 less per case than the system costs for patients who underwent arthroplasty procedures. The average length of stay for patients who underwent total ankle arthroplasty was 1.6 days compared to outpatient surgical centers utilized for most arthrodesis patients. Overall, patients reported improved pain and a 30.96 increase in FAAM scores. Most patients had a global rate of change that was “very much better” or “much better” (68%). Based on insurance type, patients who underwent a total ankle replacement in the CJR program had improved outcomes and lower cost than patients commercially insured. Conclusion: With the CJR, there is greater emphasis on the optimal intervention for elective operations. There should be coordinated efforts to optimize quality care, while minimizing financial waste within the healthcare system. The price differential suggests an annual potential for financial savings as high as $325,000 for a system that supports intervention for ~50 cases per year. As such, these results suggest that arthroplasty may be optimal for patients with severe symptomatic ankle arthritis, while most patients have adequate relief with an ankle fusion. More importantly, quality improvement efforts should focus on the impact of surgical intervention on functional activity.

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.

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