Failed Total Ankle Arthroplasty Research Articles

Total Ankle Arthroplasty Polyethylene Wear Varies with Implant Type and Mode of Failure

Introduction/Purpose: Polyethylene wear is a concern for failure of any joint replacement, including total ankle arthroplasty (TAA). Heterogeneity in bearing surface design among current TAA systems show no clear solution to the competing objectives of function (constraint and kinematics) and wear (contact stresses). Literature has begun to investigate polyethylene wear and damage; however, a comprehensive understanding of polyethylene wear patterns in vivo and location remains unknown. This study aims to quantify the type and severity of differing damage modes on the polyethylene insert from retrieved TAA prostheses following reoperation or revision. We hypothesized that polyethylene wear amount will be greater in TAAs that underwent revisions rather than reoperation, and that wear would vary between implants based on extent of constraint. Methods: This is a retrospective study of TAA patients (2007-2021) who underwent revision (removal of polyethylene and tibial and/or talar components) or reoperation (removal of polyethylene only) following primary TAA with a symmetric bicondylar (SB) implant with more constraint or an asymmetric bicondylar (AB) implant with less constraint. Demographics and surgical data were recorded. Retrieved polyethylene inserts were examined microscopically to characterize wear patterns according to a standardized protocol. Polyethylenes were divided into four regions on both the articular and backside surfaces: 1) lateral anterior, 2) lateral posterior, 3) medial anterior, and 4) medial posterior. Each region was graded by two independent raters on a scale of 0-3 based on severity for each of the following damage modes: 1) burnishing, 2) pitting, 3) scratching, 4) third body debris, 5) abrasion, 6) surface deformation, and 7) delamination. We assessed associations between polyethylene wear pattern and severity with implant type, revision, and reoperation. Results: 55 TAAs underwent revision (n=28) or reoperation (n=27). 30 (55%) ankles had primary TAA with AB implants (Salto Talaris) and 25 (45%) with SB implants (Inbone/Infinity) (Table 1). SB cohort had a shorter mean in-body duration (time from polyethylene implant to polyethylene explant) versus AB cohort (P=0.011). SB cohort had significantly greater overall polyethylene damage severity (P=0.007) and greater damage severity in all articular regions versus AB (P≤0.035 for all). Burnishing was significantly greater in SB versus AB (P < 0.001). TAAs that underwent revision had significantly greater overall damage severity versus reoperation (P=0.005), with significantly greater damage severity on articular medial posterior (P=0.003), lateral anterior (P=0.001), and lateral posterior (P=0.004) regions. Scratching (P=0.005), pitting (P < 0.001), and third body debris (P=0.036) were significantly greater in revision TAAs. Conclusion: While damage modes between SB and AB total ankle implants were similar, ankles with primary SB implants exhibited greater overall polyethylene damage severity in comparison to AB implants, despite being in-body for a shorter duration. In accordance with existing literature for total knee arthroplasty, this may suggest increased polyethylene damage severity with increased constraint. Irrespective of time in-body, failure for revision was associated with greater polyethylene damage than reoperation. This study provides the foundation for additional analyses to investigate radiographic alignment, mode of failure, and, ultimately, the association between polyethylene wear, peri-implant cysts and lucency, and TAA failure. Table 1 Patient demographics, revision, reoperation, and polyethylene in-body duration for the two patient cohorts: Patients with primary TAA with a symmetric bicondylar (SB) implant with more constraint and patients with primary TAA with an asymmetric bicondylar (AB) implant with less constraint. Values are expressed as means ± standard deviation for continuous variables, and frequencies with percentages for categorical variables. P-values reflect chi-square analyses and t tests between the two cohorts for categorical variables and continuous variables, respectively. SB cohort had significantly lower percentage of females, higher body weight, and shorter in-body duration. There was no significant difference in reoperations and revisions between the two groups.

Preliminary Experience With Commercially Available Trabecular Metal Tibial Cones Combined With a Retrograde Locked Intramedullary Nail for Bony Defects in Tibiotalocalcaneal Arthrodesis.

Critical sized bone defects in the ankle are becoming increasingly more common in patients undergoing limb reconstruction with tibiotalocalcaneal arthrodesis. Bulk allografts have not fared well over time. There have been scattered preliminary reports using custom spinal cages or 3D-printed Titanium Implants to address the critical bony defect; however, the cost of these devices is prohibitive in many clinical practice settings. The purpose of this investigation is to report the preliminary experience using a commercially available Trabecular Metal (Zimmer-Biomet) tibial metaphyseal cone combined with a retrograde locked intramedullary nail to address this challenging problem. Eight consecutive patients underwent tibiotalocalcaneal arthrodesis using a commercially available Trabecular Metal tibial metaphyseal cone combined with a retrograde locked intramedullary nail. Five developed bone loss secondary to neuropathic (Charcot) bony resorption and 3 underwent surgery for failed total ankle arthroplasty. All 8 patients eventually achieved clinical and radiographic healing and were able to ambulate with standard footwear. One patient developed a postoperative wound infection at the site of calcaneal locking screws, which resolved with debridement and parenteral antibiotic therapy. Critical bone defects about the ankle have successfully addressed with custom 3D titanium implants. This small series suggests that similar clinical outcomes can be achieved with the use of a commercially available porous tantalum metaphyseal spacer borrowed from our arthroplasty colleagues, combined with the use of a retrograde locked intramedullary nail.Levels of Evidence: Level 4: Retrospective case series.

Long-Term Survival Analysis of 5619 Total Ankle Arthroplasty and Patient Risk Factors for Failure.

Total ankle arthroplasty (TAA) has higher complication and failure rates compared to other surgical joint replacement procedures despite technological advances. This study aimed to find the long-term survivability of the TAA procedure and identify the patient risk factors for failure with one of the largest cohorts of patients in the literature. This retrospective cohort study involving cases between 2007 and 2018 analyzed patients who received an index primary TAA procedure in Korea. A total of 5619 cases were included in the final analysis. The TAA failure was defined as either a case with revision arthroplasty or a case with TAA implant removal and arthrodesis performed after primary TAA. During the study period, the 5-year survival rate was 95.4% (95% CI, 94.7-96.1%), and the 10-year survival rate was 91.1% (95% CI, 89.1-93.1%). A younger age (<55 years, adjusted hazard ratio [AHR], 1.725; 55-64 years, AHR, 1.812; p < 0.001 for both), chronic pulmonary disease (AHR, 1.476; p = 0.013), diabetes (AHR, 1.443; p = 0.014), and alcohol abuse (AHR, 1.524; p = 0.032) showed a significantly high odds ratio for primary TAA failure in Cox regression analysis. The 10-year TAA survivorship rate was 91.1%. A younger age, chronic pulmonary disease, diabetes, and heavy alcohol consumption are risk factors for TAA.

Fusion after a failed primary total ankle arthroplasty.

When a total ankle arthroplasty (TAA) fails, it can be converted to a fusion or a revision arthroplasty. Despite the increasing numbers of TAAs being undertaken, there is little information in the literature about the management of patients undergoing fusion following a failed TAA. The primary aim of this study was to analyze the survival of fusions following a failed TAA using a large dataset from the National Joint Registry (NJR). A data linkage study combined NJR and NHS Digital data. Failure of a TAA was defined as a fusion, revision to a further TAA, or amputation. Life tables and Kaplan-Meier graphs were used to record survival. Cox proportional hazards regression models were fitted to compare the rates of failure. A total of 131 patients underwent fusion as a salvage procedure following TAA. Their mean age was 65.7 years (SD 10.6) and 73 (55.7%) were male. The mean follow-up was 47.5 months (SD 27.2). The mean time between TAA and fusion was 5.3 years (SD 2.7). Overall, 32 (24.4%) underwent reoperations other than revision and 29 (22.1%) failed. Of these 24 (18.3%) underwent revision of the fusion and five (3.8%) had a below-knee amputation. No patients underwent conversion to a further TAA. Failure usually occurred in the first three postoperative years with one-year survival of fusion being 96.0% (95% confidence interval (CI) 90.7 to 98.3) and three-year survival in 69 patients being 77.5% (95% CI 68.3 to 84.4). Salvage fusion after a failed TAA shows moderate rates of failure and reoperations. Nearly 25% of patients required revision within three years. This study is an extension of studies using the same methodology reporting the failure rates and risk factors for failure, which have recently been published, and also one reporting the outcome of revision TAA for a failed primary TAA, using the same methodology, which will shortly be published.

Clinical and Radiographic Outcomes of Revision Total Ankle Arthroplasty using a Revision Ankle System

Category: Ankle Arthritis; Ankle Introduction/Purpose: With the growing popularity of total ankle arthroplasty (TAA), revision surgeries are inevitable and expected to significantly increase over the next decade. Revision TAA remains a significant challenge with high complication rates. No previous study has reported on outcomes following revision TAA using an implant designed specifically for revisions. Theoretical benefits of a revision-specific ankle system include tibial and talar fixation/stability, restoration of joint height, coverage of bone loss/defects, and maximal talar coverage. The purpose of this study was to investigate radiographic and clinical outcomes at a minimum of 2 years following revision TAA using a revision-specific ankle system. Methods: Patients who underwent a revision TAA using a revision-specific ankle system (Invision, Stryker, Kalamazoo, MI) between January 2016 and December 2020 were eligible to be included in this study. Patients with less than 2-year follow-up and unwilling to return to clinic were excluded. Overall, 25 patients met inclusion criteria. Indications for revision TAA (Table 1) included talar loosening (n = 6), tibial loosening (n = 7), talar subsidence (n = 6), re-implant after infection (n = 4), instability (n = 3), periprosthetic fracture (n = 2), and severe osteolysis (n = 2). Medians and interquartile ranges (IQRs) were reported since the data was not normally distributed. Clinical and radiographic outcomes, complications, reoperations, and implant survival was recorded. Results: Implant survival was noted in 80% of patients (20/25) at a median of 3.8 years following revision TAA. Index revision was most commonly performed for implant loosening (tibia 28%, talus 24%), talar subsidence (24%), or re-implant after infection (16%). Foot and Ankle Ability Measure (FAAM) Activities of Daily Living and Sports scores were 53.9 (IQR 46.4, 71.4) and 37.5 (IQR 21.9, 46.9), respectively at final follow-up. There was evidence of talar loosening in 3 patients (12%) and talar subsidence in 5 patients (20%) on final radiographs. Reoperation rate at final follow-up was 48%, most commonly for talar loosening/subsidence (n= 2), tibial loosening (n = 3), septic TAA (n = 1), medial/lateral gutter impingement (n = 2), and instability (n = 2). Conclusion: At a minimum follow-up of 2 years, 80% of patients retained their metal revision TAA, but reoperation rates were high with 48% of patients requiring an additional procedure most commonly for implant loosening, talar subsidence, gutter impingement, or instability. Revision TAA using a revision-specific ankle system is a viable option for patients with a failed TAA. Physicians and patients should be aware that revision TAA remains a significant challenge with a high risk of complication and reoperation rates.

Outpatient Total Ankle Arthroplasty (TAA) as a Safe and Lower Cost Alternative to Inpatient TAA

Category: Ankle; Other Introduction/Purpose: Joint replacement procedures have traditionally been performed in an inpatient setting to minimize complication rates. While the Centers for Medicare and Medicaid Services (CMS) have made provisions for outpatient total hip and knee arthroplasty, Medicare patients undergoing total ankle arthroplasty (TAA), until recently, required inpatient admission. There is growing evidence that TAA can safely be performed as an outpatient procedure, with the benefit of decreased healthcare expenses and improved patient satisfaction. Studies have largely investigated direct costs associated with TAA. The purpose of our study was to compare payer costs and complication rates between inpatient and outpatient TAA using a large publicly available for-fee database. Methods: The PearlDiver Database was queried to identify TAA-associated claims for all payer types from January 2010 to April 2021. The claims were identified by the following ICD and CPT codes and analyzed based on service location: CPT-27700, CPT- 27702, ICD-9-P-8156, ICD-10-P-0SRF07Z, ICD-10-P-0SRF0JZ, ICD-10-P-0SRF0KZ, ICD-10-P-0SRG07Z, ICD-10-P-0SRG0JZ, ICD-10-P-0SRG07Z. Baseline comparisons of age, Charleston Comorbidity Index (CCI), geographic region, and payer type were performed. Total reimbursement amount for all associated claims was summed and divided by the number of patients assigned to those claims for the average amount paid per patient. Total cost over a 90-day period was calculated by summing the cost of all claims assigned to patients who underwent TAA within this time frame. The data were analyzed for postoperative infections and readmissions within 90 days as well as failure of TAA defined as conversion to ankle arthrodesis, revision ankle arthroplasty, and/or infection requiring postoperative irrigation and debridement. Results: A total of 7,520 patients who underwent outpatient TAA and 10,772 patients who underwent inpatient TAA were identified. The average age was 54.3 years for outpatients and 63.9 years for inpatients (p Conclusion: In patients undergoing TAA, both average paid per patient and total cost within 90 days were significantly lower in the outpatient setting. Patients who underwent TAA in the outpatient setting as compared to the inpatient setting were younger, with a lower comorbidity index and a different distribution by geographic region and payer type. Complication rates including postoperative infections, readmissions, and arthroplasty failures were significantly lower in the outpatient setting, perhaps due to differences in baseline patient characteristics. These data suggest that outpatient TAA is a safe and lower cost alternative to inpatient TAA.

Revision Total Ankle Arthroplasty Outcomes in a Large Single-Center Series: Evaluation of Coronal Plane Deformity Correction and Patient Reported Measures

Category: Ankle Arthritis Introduction/Purpose: As total ankle arthroplasty (TAA) rises in popularity nationwide, the incidence of major complications and need for revision TAA will continue to increase. A better understanding of the ability to durably correct deformity and improve patient reported outcomes (PROs) in the TAA revision setting is paramount for surgeons facing the impending wave of failed TAA. Thus, the purpose of this study was to present the largest single-center case series of revision TAA to date and to evaluate improvement in PROs and maintenance of correction of coronal plane deformity in patients undergoing this procedure. Methods: This was a single-center, retrospective review of 87 revision TAAs performed between 2007 and 2022. Reoperations for cyst formations only or without metallic component exchange were excluded. The two most common implants used for revision TAA were Inbone II (n=65) and Inbone I (n=14). Mean follow-up was 2.8 ± 2.9 years. Data on patient preoperative characteristics, concurrent procedures, and postoperative complications were collected. The primary outcome measures were time to major complication, reoperation, and infection. Secondary outcomes included PROs and correction of coronal plane deformity measured from both the tibial plafond and talar articulating surface from pre- to post-operatively. Cox regression analyses were performed to compute survivorship. Results: The most common concurrent procedures performed concomitantly with revision TAA were gastrocnemius recession (n=31, 35.6%), subtalar arthrodesis (n=18, 20.7%), and talonavicular arthrodesis (n=5, 5.7%). Mean preoperative coronal plane deformity measured off both the tibial plafond and talar articular surface improved after revision TAA. 1- and 5-year survivorship from major complication, reoperation, and infection is shown in Table 2. Fourteen patients underwent subsequent revision, including TAA (n= 6, 6.9%), arthrodesis (n= 4, 4.6%), below-the-knee amputation (n= 2, 2.3%), or implantation of an antibiotic spacer (n= 2, 2.3%). At one-year postoperatively, mean VAS pain score, SF36, and AOFAS Hindfoot score was 18.2 ± 16.0, 73.0 ± 13.3, and 68.8 ±:9.3, respectively, representing an improvement in PROs after revision TAA. Conclusion: In the largest single-center series of patients undergoing single or double component exchange revision TAA, we demonstrate durable improvements in coronal plane deformity measured off both the tibial plafond and talar articular surface. We also noted 63.0% survivorship with regards to reoperation and improvements in average PROs across the cohort. Overall, revision TAA is a successful procedure, but is associated with higher failure rates at 5 years than primary TAA.

Ballooning Periprosthetic Osteolysis Related to Crystalline Arthropathies Following Total Ankle Arthroplasty: A Case Series

Category: Ankle Arthritis; Basic Sciences/Biologics Introduction/Purpose: From 2009-2019, there has been a 120% increase in the incidence of total ankle arthroplasty (TAA) in the United States. With the rise in primary TAA, future increases in revision TAA cases is anticipated. Aseptic loosening with periprosthetic osteolysis continues to account for a significant number of revisions. While several factors may contribute to the pathophysiology of osteolysis, an underlying inflammatory response surrounding TAA implants may play a primary role. It is well known that monosodium urate (gout) and calcium-pyrophosphate (pseudo-gout) crystals evoke a highly inflammatory response and may involve the foot and ankle joints. However, the effect of these conditions following TAA has not yet been reported. We present a small case series of patients with ballooning osteolysis following TAA with confirmed crystalline arthropathy. Methods: This is a retrospective study from a single academic institution looking at patients who underwent TAA revision surgery for periprosthetic osteolysis and concern for aseptic loosening. Revision surgeries were performed by three orthopedic foot and ankle fellowship trained surgeons. Case characteristics, including pre-operative imaging, clinical presentations, intra-operative findings and surgical treatments performed were analyzed and presented in this small case series. Results: We report 5 patients whom underwent revision surgery for ballooning periprosthetic osteolysis following TAA. Intra- operative pathology samples from periprosthetic cysts returned positive for monosodium urate (MSU) or calcium pyrophosphate (CPP) crystalline deposition (1 MSU and 4 CPP) in all 5 patients. Final intra-operative cultures were all negative for infection. Upon gross intra-operative inspection, all polyethylene liners were considered to be normal without abnormal wear characteristics. Periprosthetic cysts were isolated to the tibial component in 2 patients and involved both the tibial and talar components in 3 patients. Staged TAA revision was performed in 2 patients. Bone cyst curettage, bone grafting and polyethylene liner exchange was performed in 3 patients. Conclusion: Periprosthetic osteolysis is a known complication following TAA and often leads to implant loosening, functional disability and subsequent revision surgery. An objective strategy for management of this condition has not been agreed upon amongst orthopedic foot and ankle surgeons, as uncertainty remains surrounding the pathophysiology of osteolysis in TAA. To our knowledge, we are the first to describe a small case series of patients with crystalline arthropathy as a potential cause for periprosthetic osteolysis following TAA. Future prospective studies are warranted to better elucidate this potential cause of TAA failure.

Metal debris release is commonly seen from explanted total ankle replacements

This study aimed to characterise the damage mechanisms present on the metal components used in various contemporary total ankle replacements. Twenty-seven explanted total ankle replacements comprising 8 different designs (3 fixed bearing and 5 mobile bearing) were analysed using various explant analysis techniques. Pitting and scratching were the most commonly observed wear features. Microscopic analysis revealed metallic pitting on 52% of tibial components and 95% of talar components. Pitting was identified on more cobalt-chromium than titanium alloy tibial components (63% versus 0%). Non-contact profilometry confirmed the presence of pitting, with significant (p < 0.05) differences in the measured average surface roughness values of pitted and unpitted areas for tibial and talar components. There was macroscopically visible sliding plane scratching, indicating the presence of hard third body particles, on 78% of talar components. Changes to the non-articulating surfaces coatings in terms of coating loss and/or changes in reflectivity was identified visually on 80% of metal components. Scanning electron microscopy with energy dispersive X-ray spectroscopy identified metallic embedded debris in 19% of polyethylene inserts. This explant study demonstrates the release of metal debris from both the metallic tibial and talar component articulating surfaces and non-articulating surface coatings of various contemporary total ankle replacements. Metal particulate debris release from total ankle replacements may be more common than previously recognised. Metal debris should be considered in further study into the aetiology of failed total ankle arthroplasty.

Tibiotalocalcaneal arthrodesis with femoral head allograft, external fixator provisional compression, and locking plate fixation after failed total ankle arthroplasty

The number of total ankle arthroplasties has increased in recent years with the improvement of implants and advanced attempts to maintain ankle movement. However, this technique presents complications, such as aseptic loosening and infection, requiring revision surgery. In this scenario, conversion by tibiotalar or tibiotalocalcaneal arthrodesis is highly accepted and can be performed with external fixators, intramedullary rods, screws, or locking plates. This article shows the resolution of a case of aseptic loosening tibiotalocalcaneal arthrodesis fixed with a locking plate associated with bone allograft. Level of Evidence V; Therapeutic Studies; Expert Opinion.

Metal Hypersensitivity Following Total Ankle Arthroplasty: Case Series and Literature Review

Metal hypersensitivity following total ankle arthroplasty (TAA) is an underreported complication that can manifest as dermal, systematic, and orthopaedic-specific symptoms. It is critical to recognize that metal hypersensitivity is a diagnosis of exclusion; only after all other potential sources of failure, such as loosening or infection are ruled out, can this diagnosis be considered. Aside from imaging and common laboratory analysis, skin patch testing, leukocyte migration inhibition test (LMIT), and lymphocyte transformation test (LTT) are the testing options available for metal allergy. With regards to management of metal hypersensitivity, nonoperative modalities involving topical dermatological management are generally preferred. Severe cases of metal allergy may necessitate operative management consisting of explantation of the implant and either revision TAA with a custom hypoallergenic implant or conversion to an ankle fusion. We present 3 cases of presumed metal hypersensitivity following TAA. In all 3 cases, other forms of TAA failure were carefully ruled out. One patient underwent explantation and conversion to hypoallergenic implant, 1 patient underwent explantation and ankle arthrodesis with hypoallergenic hardware, and 1 patient elected for conservative care. In patients who underwent explantation and conversion to hypoallergenic hardware, no further symptoms associated with metal allergy were noted. Additional research is necessary to improve diagnostic accuracy of metal allergy and make treatment options more effective and accessible.Level of Evidence: Retrospective case series, IV.

Foot &amp; Ankle

The February 2023 Foot &amp; Ankle Roundup360 looks at: Joint inflammatory response in ankle and pilon fractures; Tibiotalocalcaneal fusion with a custom cage; Topical application of tranexamic acid can reduce blood loss in calcaneal fractures; Risk factors for failure of total ankle arthroplasty; Pain catastrophizing: the same as pain forecasting?.

Failure rates and patient-reported outcomes of revision of total ankle arthroplasty.

Despite the increasing number of revision total ankle arthroplasty (TAA), the literature on indications, surgical options, and outcomes is limited. This study reports on failure rates and patient-reported outcomes (PROM) for a cohort of 122 patients who underwent revision of TAA. A retrospective review of revision TAA between 2006 and 2020 was performed at one institution. Patient's demographics and different surgical procedures were analyzed with particular attention to comparing polyethylene exchange with revision of both metallic components and to additional interventions for axis correction. Failure rates and the European Foot and Ankle Society (EFAS) score were collected. The average follow-up period was 70.37 ± 46.76months. 122 patients were treated with an exchange procedure. The surgery included 69 polyethylene exchanges, 12 revisions of one metallic component, and 41 revisions of both metallic components. The overall failure rate was 14.75%. The EFAS score, completed by 94 of the 122 patients, was used to evaluate clinical outcomes. Median EFAS score was 12.51 ± 5.53, and median EFAS sports score was 2.97 ± 3.04. Revision rates after polyethylene exchange were significantly higher than after exchanging both metallic components (p value = 0.03), while the EFAS score showed slightly better results in patients treated with polyethylene exchange. Adding procedures to induce axis correction led to significantly lower revision rates (p value = 0.03), and the EFAS score was also improved but without statistical significance. The high failure rate of polyethylene exchange indicates that the intervention does not address the actual cause of failed TAA in many cases. Additional axis correction should be considered more frequently. If the underlying issues of prosthesis failure can be identified and sufficiently addressed, the results of revision surgery are likely to improve.

Total Ankle Arthroplasty for Post-Traumatic Fracture vs Primary Osteoarthritis: An Analysis of Complications, Revisions, and Implant Survival

Category: Ankle Arthritis; Ankle Introduction/Purpose: Total ankle arthroplasty (TAA) has been shown to provide satisfactory clinical outcomes for the treatment of end-stage tibiotalar arthritis. However, most outcome studies do not discriminate by arthritis etiology, and there are currently no large-scale studies comparing outcomes of TAA performed for primary osteoarthritis (POA) versus post-traumatic osteoarthritis secondary to fracture sequelae (PTOA). The purpose of this study was to investigate the effect of arthritis etiology on post-operative complications, revision rates, and implant survival of TAA. Methods: 143 patients that underwent TAA for POA (n=68) and PTOA (n=75) between January 2014 and May 2021 were retrospectively evaluated. Surgeries were completed by a single fellowship-trained surgeon utilizing the same Stryker STAR implant for all cases. Patient demographics, postoperative complications, and revision surgery profiles were collected with a mean follow-up of 21 +- 19 months (Range 1.4 months-6.4 years). Based on a severity classification proposed by Gadd et al, complications were divided into low and high risk for TAA failure. Other complications (arthrofibrosis, impingement, periprosthetic cystic changes, Achilles tendinitis, persistent instability, and PTT dysfunction) were also collected. Logistic regression was used to analyze the relationship between patient demographics, osteoarthritis etiology, and complications. Categorical variables were compared with Chi-square tests, means with a two-tailed Student's t-test, and implant survival was assessed with a Kaplan-Meier analysis and Mantel-Cox logrank test. Significance was defined as p&lt;.05 for all statistical analyses. Results: Cohort demographics were comparable except that POA patients were significantly older (65+-9 years) than PTOA patients (57+-13 years) (p&lt;.001). There was no difference in rate of low risk (16.2% vs. 9.3%) (p=.218), high risk (13.2% vs. 16%) (p=.641), or other complications (14.7% vs 22.7%) (p=.224) between POA and PTOA. This remained true when controlling for patient demographics. At 7 years, TAA survival with implant retention revision as an endpoint was comparable between POA (91.2%) and PTOA (93.3%) (p=.615), with no difference in mean time to revision between POA (5+-4 months) and PTOA (16+-21 months) (p=.27). With TAA explant as an endpoint, greater survival trended in POA (100%) as compared to PTOA (94.6%) (p=.056) (Figure 1). Mean time to TAA explant for PTOA was 13+-7 months. Failure etiologies included symptomatic arthrofibrosis, component subsidence, periprosthetic fracture, and aseptic loosening. Conclusion: The complications, revision rates, and 7-year survivorship of TAA using a single prosthesis for PTOA secondary to fracture sequelae were no different when compared to TAA for POA. However, there was a non-significant trend for an increased rate of implant failure requiring TAA explant in PTOA compared to POA (Figure 1). Given this trend, further investigation is warranted to assess the long-term outcomes and implant survival of total ankle arthroplasty for post-traumatic fracture osteoarthritis.

Clinical and Radiographic Outcomes of Revision Total Ankle Arthroplasty Using the INBONE II Prosthesis.

The literature on the outcome of revision total ankle arthroplasty (TAA) remains limited. In this study, we aimed to report the clinical and radiographic outcomes of revision TAA at a high-volume center in the United Kingdom. This study was a retrospective review of 28 patients who underwent 29 revision TAAs using the INBONE II Total Ankle System (Wright Medical Technology/Stryker). Demographic, radiographic, and patient-reported outcome measure data were analyzed. The mean duration from primary TAA to revision was 87.5 months (range, 16 to 223 months). The main indication for the revision was aseptic loosening after the primary TAA (83%). Additional procedures were required in 76% of ankles. At a mean follow-up of 40 months (range, 24 to 60 months), the infection rate was 7%, the reoperation rate was 7%, and the implant survival rate was 97%. A significant postoperative improvement in the radiographic component alignment measures was observed. The subsidence, loosening, and heterotopic ossification rates in this study were comparable with those in other reports and did not influence the clinical outcome. A significant improvement was observed in the Manchester-Oxford Foot Questionnaire (MOXFQ) in all domains and the EuroQol-5 Dimensions (EQ-5D) in 3 domains at 24 months postoperatively. Revision TAA using the INBONE II prosthesis was associated with good short-term survival and improvement in postoperative scores at 2 years. Maintenance of the postoperatively improved alignment was documented at the follow-up. The results of this study support the notion that revision TAA is a satisfactory option for failed primary TAA. Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Comparison of joint load, motions and contact stress and bone‐implant interface micromotion of three implant designs for total ankle arthroplasty

Background and ObjectiveLoosening and wear are still the main problems for the failure of total ankle arthroplasty, which are closely related to the micromotion at the bone-implant interface and the contact stress and joint motions at the articular surfaces. Implant design is a key factor to influence the ankle force, motions, contact stress, and bone-implant interface micromotion. The purpose of this study is to evaluate the differences in these parameters of INBONE II, INFINITY, and a new anatomic ankle implant under the physiological walking gait of three patients. MethodsThis was achieved by using an in-silico simulation framework combining patient-specific musculoskeletal multibody dynamics and finite element analysis. Each implant was implanted into the musculoskeletal multibody dynamics model, respectively, which was driven by the gait data to calculate ankle forces and motions. These were then used as the boundary conditions for the finite element model, and the contact stress and the bone-implant interface micromotions were calculated. ResultsThe total ankle contact forces were not significantly affected by articular surface geometries of ankle implants. The range of motion of the ankle joint implanted with INFINITY was a little larger than that with INBONE II. The anatomic ankle implant design produced a greater range of motion than INBONE II, especially the internal-external rotation. The fixation design of INFINITY achieved lower bone-implant interface micromotion compared with INBONE II. The anatomic ankle implant design produced smaller contact stress with no evident edge contact and a smaller tibia-implant interface micromotion. In addition, significant differences in the magnitudes and tendencies of total ankle contact forces and motions among different patients were found. ConclusionsThe articular surface geometry of ankle implants not only affected the ankle motions and contact stress distribution but also affected the bone-implant interface micromotions. The anatomic ankle implant had good performance in recovering ankle joint motion, equalizing contact stress, and reducing bone-implant interface micromotion. INFINITY's fixation design could achieve smaller bone-implant interface micromotion than INBONE II.

Ankle/Hindfoot Arthrodesis as a Salvage Procedure for Failed Total Ankle Arthroplasty

Category:Ankle; HindfootIntroduction/Purpose:High failure rate after total ankle arthroplasty (TAA) in 10-year follow-up has been reported, ranging from 10 to 20%. Massive bony destruction after TAA often caused by periprosthetic osteolysis, implant subsidence or loosening, or periprosthetic infection, and it would be considerable challenge to many orthopedic surgeons. In some cases, it is difficult to perform revision arthroplasty. For failed TAA, ankle/hindfoot arthrodesis can be performed as a salvage procedure. In this study, we evaluate the clinical and radiologic outcomes of the ankle/hindfoot arthrodesis in patients with failed TAA.Methods:Ankle/hindfoot arthrodesis was performed in 10 ankles with failed TAA from October 2003 to March 2019 (at least 6- month follow-up). As for the clinical evaluation, visual analogue scale (VAS) pain scores, and American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scores were assessed. Postoperative complications such as skin necrosis, surgical site infection (SSI), or non-union were reviewed through medical records. Radiographs including CT images at last follow-up were assessed to confirm bone union.Results:The average follow-up was 49.1 months (range, 7-89). There were 6 cases performed with tibiotalocalcaneal (TTC) arthrodesis, and 4 cases with ankle arthrodesis. The operations were performed at mean postoperative 46.6 months (range, 8- 178) from index TAA. Allo-femoral head structural bone graft was used in 9 cases, and auto proximal tibia cancellous bone graft was used in 5 cases. Mean VAS pain score decreased from 7.6 pre-operatively to 2.2. AOFAS score increased from 15.6 to 42.0 (subjective assessment only; maximum score=68). 3 revision surgeries had been performed after initial arthrodesis (1 case for SSI, 2 cases for non-union), and bone union was obtained in 2 cases (1 case of SSI, 1 case of non-union).Conclusion:Ankle/hindfoot arthrodesis after failed TAA can be optimal surgical option for the patients with massive bony destruction which compromises revision arthroplasty. It acts as a salvage procedure for failed TAA and could yield favorable outcome.

Ankle-Hindfoot Reconstruction by Tibiotalocalcaneal (TTC) Arthrodesis Using Multiple Cannulated Screws: 32 Cases

Category:Ankle; Ankle ArthritisIntroduction/Purpose:Tibiotalocalcaneal (TTC) arthrodesis is a salvage procedure that can be used as an alternative to amputation for various pathologic conditions of the ankle-hindfoot. The aim of this study is to evaluate the clinical-radiological outcome of TTC arthrodesis performed using the multiple cannulated screws.Methods:From 2003 to 2018, 32 ankles (31 patients) underwent TTC arthrodesis. The mean follow-up period was mean 32.5 (12-92) months and the average patient age at surgery was 59.6 years (43-75). The etiologies of TTC arthrodesis included posttraumatic osteoarthritis (18.8%), Charcot arthropathy (18.8%), paralytic deformity (21.9%), failure of total ankle arthroplasty (9.4%), and failure of arthrodesis (9.4%). For all of 32 cases, transfibular approach was used with or without auto fibular cancellous bone graft. 7.3mm cannulated screws were used for fixation of arthodesis for all of 32 cases, and in 23 of 32 cases (71.9%), screw- fixation was used exclusively without any additional plate or Ilizarov fixator. Especially for 11 of 32 cases with large bony defect, fresh-frozen allo-femoral head structural bone graft was used. Pre- and postoperative visual analog scale (VAS) pain, the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot functional score, and radiographs including CT images were assessed.Results:Overall union rate was 81.3% (26/32). Mean VAS score decreased from 6.92 preoperatively to 1.46 postoperatively and the AOFAS score improved from 27.0 to 53.7 (Max=68) at the final follow-up. Complication of TTC arthrodesis included nonunion (18.8%, 6/32), infection (12.5%, 4/32), and one case of skin necrosis. Most frequent nonunion site was tibiotalar joint (6/32). For 3 of 7 cases with nonunion, patients were painless and could ambulate without severe functional impairment. There were two cases with infective nonunion and one case with active Charcot arthropathy after artrhdesis. Union rate of two groups with/without allo-femoral head bone graft were similar to each other (81.8%, 81.0%, respectively), however, final AOFAS scores were significantly superior in 'without' femoral head bone graft group.Conclusion:This study achieved a fusion rate comparable to other previous studies and obtained favorable clinical outcomes. Realignment TTC arthrodesis using multiple cannulated screws is a valid surgical option as a salvage procedure for various deformed or arthritic conditions of ankle-hindfoot. Allo-femoral head structural bone graft can be selected as useful option for TTC arthrodesis with large bone defect.

Risk factors associated with failure of total ankle arthroplasty: a nationwide cohort study

We conducted a nationwide population-based cohort study to identify the risk factors associated with failure of total ankle arthroplasty (TAA). We included 2,914 subjects who underwent primary TAA between January 1, 2010, and December 31, 2016, utilizing the database of the Korean National Health Insurance Service. Failure of TAA was defined as revision TAA or arthrodesis procedures. An increased risk of TAA failure was observed in the < 65 age group versus the ≥ 75 age group [adjusted hazard ratios (aHR) 2.273, 95% confidence interval (CI) 1.223–4.226 in the 60–64 age group; aHR 2.697, 95% CI 1.405–5.178 in the 55–59 age group; aHR 2.281, 95% CI 1.145–4.543 in the 50–54 age group; aHR 2.851, 95% CI 1.311–6.203 in the < 50 age group]. Conversely, the ≥ 65 age group displayed no increase in the risk of TAA failure. The risk of TAA failure was increased in the severely obese group with body mass index (BMI) of ≥ 30 kg/m2 versus the normal BMI group (aHR 1.632; 95% CI 1.036–2.570). This population-based longitudinal study demonstrated that age < 65 years and BMI of ≥ 30 kg/m2 were associated with increased risk of TAA failure.

Risk Factors for Early Failure of Fourth Generation Total Ankle Arthroplasty Prostheses

A number of 2-component, fourth generation total ankle arthroplasty (TAA) prostheses have been introduced to the market in the past few years, as the popularity and indications for TAA have continued to expand. The purpose of the present study was to identify independent risk factors for the early failure of fourth generation TAA prostheses. A total of 97 ankles underwent TAA with a fourth generation prostheses (INFINITY, CADENCE) between August 2015 and June 2018 at a single institution and were at least 6 months postoperative (mean 18.3 months, range 6-43). The primary outcome assessed was the need for revision surgery, defined as removal of 1 or both metal components for any reason, excluding infection. Baseline patient demographics, characteristics, radiographic alignment parameters, and distal tibia cortical bone thickness (CBT) were assessed. Revisions, reoperations, and complications were classified according to the criteria established by Vander Griend et al and Glazebrook et al, respectively. Univariate and multivariate analyses were performed. Three ankles (3.1%) underwent revision surgery for aseptic loosening at a mean of 24.3 (range, 16-31) months; all had a CBT <4 mm. Independent predictors for reoperation were CBT <4 mm, presence of diabetes, and ipsilateral hindfoot fusion (p = .04). No associations were identified for purported risk factors (age, body mass index, and coronal deformity). The present study is the first to suggest a potential relationship between reduced CBT of the distal tibia, and TAA failure. Additional studies are warranted to better understand the role of bone density in TAA survivorship.