Short-Term Complications, Reoperations, and Radiographic Outcomes of a New Fixed-Bearing Total Ankle Arthroplasty

Implant Choice May Reduce the Risk of Early Mechanical Failure in Total Ankle Replacement

BACKGROUND

Total ankle replacements (TARs) have rapidly advanced in terms of volume, technique, design, and indications. However, TARs are still at risk for early mechanical failure and revision. Prior studies have investigated potential risk factors for failure, but have been limited to smaller series or older implants. This study sought to identify risk factors for early mechanical failure in modern TAR.

METHODS

This is a retrospective study of a single-institution registry. Five surgeons contributed cases involving patients who underwent a primary TAR with any implant. Implants were grouped on the basis of the type of fixation. The primary outcome was early mechanical failure (revision with component removal for a non-infectious etiology, that is, subsidence, aseptic loosening, and/or malalignment). Logistic regression determined the effects of age, weight, hindfoot arthrodesis, implant type, and radiographic deformity on failure.

RESULTS

The 731 included patients had a mean follow-up of 2.7 years. Ten percent (71 patients) had hindfoot arthrodesis. There were 33 mechanical failures (4.5%) at a mean of 1.7 years after the index surgical procedure. Our model demonstrated that hindfoot arthrodesis was associated with 2.7 times greater odds of failure (p = 0.045), every 10 kg of body weight increased the odds of tibial-sided failure by 1.29 times (p = 0.039), and implants with more extensive tibial fixation (stems or keels) lowered the odds of tibial failure by 95% (p = 0.031).

CONCLUSIONS

In patients with uncontrollable risk factors (hindfoot arthrodesis) or risk factors that may or may not be modifiable by the patient (weight), implants with more robust tibial fixation may be able to reduce the risk of early mechanical failure. Further research is warranted to support efforts to decrease early failure in TAR.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Clinical Outcomes and Registry Data in Total Ankle Arthroplasty

Total ankle arthroplasty (TAA) is an effective treatment for end-stage ankle arthritis consistently demonstrating good to excellent outcomes, even when considering factors such as deformity, patient age, bilaterality, and arthritis etiology. There is little consensus in the literature with regard to preferred patient-reported outcome metrics (PROMs) for assessing outcomes, although all metrics generally improve following TAA. Several countries have successful registries to track longevity of TAA in populations; however, PROMs are generally not successfully tracked in registries. A trend toward consensus on outcome metrics and collaborative registries is warranted to optimize patient selection and outcomes in TAA.

Short-Term Outcomes After Bipolar Osteochondral Allograft Transplantation (OCAT) in the Ankle

Treatment options for symptomatic cartilage loss in the ankle are not consistently effective. This study documents initial outcomes for patients undergoing bipolar OCAT in the ankle after advances in tissue preservation, transplantation techniques, and patient management strategies were implemented. Patients were prospectively enrolled into a registry designed to follow outcomes after OCAT in the ankle. Fourteen patients were included for analyses (12 primary OCAT, 2 revision OCAT). Four patients underwent Bipolar OCAT (tibia, talus) and 10 Bipolar+ OCAT (tibia, talus, fibula). Short-term (median follow-up 43, range 13-73 months) success was documented for 13 patients. Radiographic assessments indicated OCA integration and maintenance of joint space in 12 patients. Statistically significant (p < .030) and clinically meaningful improvements in AAOS and VAS pain scores were noted at 3 months, 6 months, 1 year, and 2 years following OCA transplantation when compared to preoperative measures. For patients that were nonadherent to postoperative restriction and rehabilitation protocols, all 1-year postoperative PROs were significantly lower (p < .050) than for patients who were adherent. The successful outcomes documented in 13 of 14 patients in conjunction with significant and clinically meaningful improvements in patient-reported measures of pain and function support OCA transplantation as an appropriate treatment option in indicated patients. These improvements in outcomes were associated with advances in OCA preservation, preimplantation treatment, transplantation techniques, and patient management strategies, suggesting this shift in practice be considered for OCA transplantation in the ankle.

Influence of sidewall retention and interference fit in total ankle replacement on implant-bone micromotion: A finite element study

The success of uncemented total ankle replacement (TAR) is linked to initial stability because bony ingrowth depends upon limited early micromotion. Tibial implant design fixation features resist micromotion aided by bony sidewall retention and interference fit. Our goal was to investigate factors influencing implant-bone micromotion in TAR. Two TAR tibial components were virtually inserted into CT-derived computer models of two distal tibias from patients with end-stage ankle arthritis. Density-based inhomogeneous material assignment was used to model bone compaction during press-fit. Finite element analysis (FEA) was used to simulate three fixation cases: (1) no sidewalls + line-to-line fit, (2) sidewalls + line-to-line fit, and (3) sidewalls + 50, 100, or 200 µm interference fit. Kinetic profiles from the stance phase of gait were simulated and micromotions computed from FEA output. Without sidewalls or interference fit, micromotions were largest in early and late stance, with largest micromotions (averaging ~150-250 µm) observed near heel strike. Micromotions decreased 39%-62% when sidewalls were retained. When interference fit was also modeled, micromotions decreased another 37%-61% to ~10 µm. Micromotion differences between patients persisted with sidewall retention but largely disappeared with interference fit. This study presents new insights into the effects of TAR fixation features on implant-bone micromotion. Stability appeared to be influenced by surrounding bone quality, but this influence was greatly diminished when interference fit was introduced. More complete understanding of TAR implant features and performance is needed, but our results show the importance of bone quality and interference fit in the stability of uncemented TAR.

Lack of Consensus on the Definition of Aseptic Loosening in Total Ankle Replacement: A Narrative Systematic Review

Background: Aseptic loosening is one of the most common modes of failure of total ankle replacement (TAR). However, a precise definition of aseptic loosening is still lacking. This systematic review aimed to identify the variations of applied definitions and offer insights into the lack of consensus. Methods: Human studies reporting aseptic loosening of TAR published in peer-reviewed journals within the last decade were considered. The search strategy involved specific terms in Embase, MEDLINE ALL, and the Cochrane Library. Variations in aseptic loosening definitions were analysed. Results: Of 767 studies, 88 were included in this study. Only nine studies precisely defined aseptic loosening with significant variations. Twenty-two studies referenced the term and fifty-seven reported it as a complication but neither defined nor referenced it. Conclusions: Significant uncertainty exists regarding the universal definition of aseptic loosening of TAR, and many variations occur in terms of the assessment approach and criteria.

Comparison of Radiographic Talar Loosening Rates Between Salto-Talaris and INBONE II

BACKGROUND

Despite substantial increase in total ankle arthroplasty (TAA) nationwide, there are few studies comparing flat-cut vs chamfer-cut talar systems in TAA with regard to radiographic aseptic loosening rates of the implant.

METHODS

This retrospective study included 189 Salto-Talaris TAA and 132 INBONE II primary TAA with a minimum 1-year follow-up. Patient characteristics were obtained including gender, age at surgery, body mass index (BMI), smoking status, primary diagnosis, surgical time, and the presence of diabetes. Radiographic evidence for aseptic loosening was assessed. Statistical analysis was performed for comparison in outcomes between Salto-Talaris and INBONE II.

RESULTS

The mean age of the study population was 63.5 ± 9.8 years at surgery. Mean follow-up was 4.9 ± 3.0 years. Radiographic aseptic loosening of the tibial implant showed no significant difference between the 2 groups: Salto-Talaris, 18%, and INBONE II, 18.9% (P = .829). Aseptic loosening of the talar implant also showed no significant difference between the 2 groups: Salto-Talaris, 1.6%, and INBONE II, 1.5% (P = .959). No variables, including the implant type, were found to contribute to the aseptic loosening rate of either the tibia or talus.

CONCLUSION

In our cohort, we observed no difference in radiographic implant aseptic loosening between Salto-Talaris and INBONE II systems.

LEVEL OF EVIDENCE

Level IV, retrospective case series study.

Two to Five-Year Outcomes of Total Ankle Arthroplasty with the Infinity Fixed-Bearing Implant: A Concise Follow-up of a Previous Report

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Midterm Clinical Outcomes, Radiographic Outcomes, and Survivorship of the Infinity Total Ankle Arthroplasty

BACKGROUND

The Infinity Total Ankle Arthroplasty (Stryker, Mahwah, NJ) is a low-profile fixed-bearing implant first introduced in 2014. Although the short-term survivorship (2-4 years follow-up) and complication rates of the Infinity TAA have been reported, there are limited midterm outcome reports. The aim of this study was to describe the survivorship and clinical outcomes of a single-center experience with the Infinity implant at minimum 5-year follow-up.

METHODS

Retrospective review of 65 ankles that underwent primary total ankle arthroplasty (TAA) with the Infinity implant was conducted. Mean clinical follow-up was 6.5 years (range, 5.0-8.0). Preoperative and postoperative radiographs were measured to assess tibiotalar alignment, periprosthetic lucencies, and cysts. Preoperative, 2-year, and 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscores were compared to assess midterm clinical outcomes. Survivorship assessment was determined by removal of 1 or both metallic implant components.

RESULTS

Survivorship of the implant was 93.8% at final follow-up. There were 4 revisions: 2 for tibial implant loosening, 1 for talar loosening, and 1 for loosening of both components. Three of the 4 revisions occurred within the first 2 years following implantation, and the last failure occurred at 7 years postoperatively. There were 11 reoperations in 10 (15%) ankles and 3 wound complications. There were 17 ankles (26.2%) with radiographic abnormalities around the implants, including 14 cases with tibial component lucencies and 4 cases of periimplant cysts. FAOS outcome measurement showed general stability between 2 and 5 years and substantial improvement from preoperative status.

CONCLUSION

To date this study is the largest midterm report on the Infinity total ankle prosthesis, with 65 implants at a mean follow-up of 6.5 years. We found good midterm implant survivorship, and patients experienced significant improvements in FAOS outcome scores and radiographic alignment at final follow-up.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Early outcomes of the Exactech Vantage fixed-bearing total ankle replacement

Aims

The Vantage Total Ankle System is a fourth-generation low-profile fixed-bearing implant that has been available since 2016. We aimed to describe our early experience with this implant.

Methods

This is a single-centre retrospective review of patients who underwent primary total ankle arthroplasty (TAA) with a Vantage implant between November 2017 and February 2020, with a minimum of two years' follow-up. Four surgeons contributed patients. The primary outcome was reoperation and revision rate of the Vantage implant at two years. Secondary outcomes included radiological alignment, peri-implant complications, and pre- and postoperative patient-reported outcomes.

Results

There were 168 patients (171 ankles) included with a mean follow-up of 2.81 years (2 to 4.6) and mean age of 63.0 years (SD 9.4). Of the ten ankles with implant failure (5.8%), six had loosening of the tibial component. In the remaining four failed implants, one was due to periprosthetic joint infection (PJI), one was due to loosening of the talar component, and two were due to loosening of both the tibial and talar components. Seven patients underwent reoperation: irrigation and debridement for superficial infection (n = 4); bone grafting for cysts (n = 2); and open reduction internal fixation (n = 1). Asymptomatic peri-implant lucency/subsidence occurred in 20.1% of ankles, with the majority involving the tibial component (n = 25). There were statistically significant improvements in PROMs in all domains.

Conclusion

Short-term results of this implant demonstrate early survival comparable to the reported survivorship of similar low-profile, non-stemmed implants. Radiological lucency occurred more commonly at the tibial component, and revisions occurred primarily due to loosening of the tibial component. Further research is needed to evaluate longer-term survivorship.

Computed Tomography Derived Patient-specific Instrumentation Total Ankle Arthroplasty Survivorship Outcomes

Computed tomography (CT) derived patient-specific total ankle arthroplasty (TAA) systems have been utilized for improved accuracy and reproducible implant alignment. The purpose of the present study was to report the overall implant survivorship as well as radiographic analysis of patients who underwent primary TAA utilizing CT-derived patient-specific instrumentation. A retrospective review of medical charts and radiographs were performed on patients who had undergone primary TAA at a single institution in the Midwest region from March 2013 to October 2020. Radiographic analysis included preoperative, initial postoperative, and final follow-up coronal and sagittal tibiotalar alignment as well as periprosthetic radiolucency. A total of 96 patients with a mean follow-up of 3 years (range, 0.3-7.3 years) were included. Implant survivorship was found to be 92% at median follow-up of 3 years. A total of 8 cases (8.3%) required revision/reoperation, with 6 (6.3%) of these reoperations directly related for failure of one of the metallic implant components. There was significant improvement in both coronal and sagittal tibiotalar alignment from preoperative to initial postoperative follow-up (p < .001). At latest postoperative follow-up, there were 88% of TAAs that remained in a neutral alignment following surgery. A total of 10 cases were found to have radiolucency at latest follow-up. In conclusion, the use of CT derived patient-specific TAA showed high implant survivorship with significant improvement of sagittal and coronal tibiotalar alignment. With better implant alignment and position, it potentially reduces the risk of early implant failure or implant loosening in long-term follow-up.

Clinical Outcomes of the Lateral Trabecular Metal Total Ankle Replacement at a 5-Year Minimum Follow-up

BACKGROUND

The Trabecular Metal (Zimmer Biomet, Warsaw, IN) total ankle arthroplasty (TAA) system uses a lateral approach with a fibular osteotomy to gain access to the tibiotalar joint and a sagittally curved tibial component. This is the first TAA system to laterally approach the ankle, and few studies have explored outcomes associated with this implant. This study aimed to report the 5-year clinical and radiographic outcomes as well as the survivorship of the implant.

METHODS

Over a 3-year period, 2 fellowship-trained foot and ankle surgeons used this implant system to treat 38 end-stage arthritic ankles. Reoperation and revision data were collected from all patients (100%) as part of the local prospective database. Patients completed the Foot and Ankle Outcome Score (FAOS) questionnaire preoperatively and at each annual follow-up visit; scores for a minimum of 5 years were available for 28 (73.7%) patients. A radiographic analysis compared postoperative coronal and sagittal alignment in weightbearing radiographs at a minimum of 5 years with that at 3 months postoperatively, as well as cyst or lucency formation, which was available for 21 patients (55.3%).

RESULTS

At 5 years, there were 3 revisions (7.9%) and 9 reoperations (23.7%). Reoperations included 4 fibular hardware removal and 5 medial gutter debridement procedures. The FAOS significantly improved for all domains (P < .05). Implant positioning did not significantly change between 3 months and 5 years postoperatively.

CONCLUSION

Our 5-year results in this small series using this unique prosthesis showed good overall survivorship (92.1%) and a reoperation rate of 23.7%, along with clinically significant improvement in patient-reported outcomes.

LEVELS OF EVIDENCE

Level IV: Retrospective case series.

Mid-term functional outcomes following reoperation after total ankle arthroplasty: A retrospective cohort study

BACKGROUND

Despite a significant reported rate of non-revision reoperation after total ankle arthroplasty (TAA), it is uncertain if these subsequent procedures have an impact on the longer term outcomes. This study aimed to compare minimum five-year functional outcomes of patients who had undergone reoperation after TAA to those who did not require reoperation.

METHODS

Seventy-six ankles (74 patients) who underwent TAA with the Salto Talaris fixed bearing system between 2007 and 2014 were allocated into two groups based on presence (n = 16) or absence of reoperation (n = 60). Reoperations included all secondary procedures after index TAA, excluding revision surgeries requiring removal or exchange of the original prosthesis. The foot and ankle outcome score (FAOS) at preoperative and minimum five-year follow-up was compared between the groups. Additionally, improvements in FAOS subscales were compared. Preoperative deformity, postoperative implant alignment, number of periprosthetic cysts, and subsidence between groups were compared using standard weightbearing radiographs.

RESULTS

The most common cause of reoperation was gutter impingement (n = 11), followed by stress fracture of the medial malleolus (n = 2), tarsal tunnel syndrome (n = 1), periprosthetic cyst (n = 1), and infection (n = 1). In comparison to the non-reoperation group, all FAOS subscales except for the Sports and Recreational Activities subscale were significantly lower in the reoperation group at final follow-up. The reoperation group exhibited significantly less improvement in the Pain, Symptoms, and Quality of Life subscales at final follow-up (p < 0.05). There were no statistical differences in the radiographic parameters between both groups.

CONCLUSIONS

Patients who underwent reoperation after TAA demonstrated inferior functional outcomes at mid-term follow-up. An emphasis should be placed on preventing possible causes of reoperations to achieve favorable patient outcomes. Additionally, if a reoperation is deemed necessary, a thorough evaluation and surgical correction of underlying causes should be achieved.

Tibial Component Subsidence in a Total Ankle System Comparing Standard Technique Versus a Hybrid Technique

Total ankle arthroplasty (TAA) is a viable treatment option for end-stage ankle arthritis. However, implant survivorship remains an important consideration. Concerns regarding early component loosening with the low-profile tibial tray utilized by fourth-generation TAA systems have been raised in the literature. We have previously described our preliminary outcomes of a hybrid technique combining a stemmed intramedullary tibial component with a chamfer-cut talar component for TAA. A retrospective study comparing short-term outcomes of the tibial component between a standard fourth-generation TAA system versus our hybrid technique was performed. 46 patients with a minimum of 1-year follow up were included in the analyses. There were 25 subjects in the standard implant cohort utilizing a low-profile tibial tray, and 21 subjects in the hybrid group utilizing a stemmed intramedullary tibial component. No statistically significant difference between the demographics of each group was found. The rate of tibial component subsidence was 8% (n = 2) in the standard implant group, and 0% (n = 0) in the hybrid group, though this did not meet statistical significance (p = .49). Mean time to subsidence was 6 months, and revision rate due to tibial component subsidence was 2.1% (n = 1). Periprosthetic lucency was present on most recent follow-up radiographs in 32% and 9.5% of ankles in the standard and hybrid groups, respectively (p = .08). Despite prior concerns for tibial component subsidence with the standard fourth-generation system, we demonstrated low rates in both implant groups. Additional studies are needed to further explore factors that may predispose patients to early tibial component subsidence and resulting implant failure.

Early Radiographic and Clinical Outcomes of a Novel, Fixed-Bearing Fourth-Generation Total Ankle Replacement System

BACKGROUND

The Cadence Total Ankle System is a 2-component, fixed-bearing fourth-generation total ankle arthroplasty (TAA) system that was introduced for clinical use in 2016. The purpose of this study was to report non-inventor, non-industry funded survivorship, radiographic and clinical outcomes, and early complications following use of this implant at a minimum of 2 years.

METHODS

This single-center retrospective study included patients who underwent TAA by 2 surgeons with this novel fixed-bearing system between January 2017 and September 2018. Forty-eight patients were evaluated at an average of 33.6 months. Radiographic outcomes included preoperative and postoperative tibiotalar angle on anteroposterior radiographs of the ankle, sagittal tibial angle (STA) on lateral radiographs of the ankle, and periprosthetic lucency formation and location. Revision and reoperation data were collected, and patient-reported outcomes were assessed using Patient Reported Outcomes Measurement Information System (PROMIS). Subgroup analysis assessed associations between preoperative deformity, postoperative implant alignment, PROMIS scores, and periprosthetic lucency formation.

RESULTS

Survivorship of implant was 93.7%, with 3 revisions, 1 due to infection and 2 due to loosening of the implant (1 tibial and 1 talar component). Three patients had reoperations (6.3%): 2 for superficial infection and 1 for gutter debridement due to medial gutter impingement. Fifteen patients (35.8%) developed periprosthetic lucencies, all on the tibial side. PROMIS scores improved after surgery in all domains except Depression. Patients with significant postoperative periprosthetic lucency had worse postoperative PROMIS Physical function scores than patients without lucency (P < .05).

CONCLUSION

This study demonstrated excellent minimum 2-year clinical and radiographic outcomes and low revision and reoperation rates of this new fourth-generation TAA system. Future studies with longer follow-up, especially on patients with periprosthetic lucency, are necessary to investigate the long-term complications and understand the long-term functional and radiographic outcomes of this implant.

Long-term Follow-up of 254 Ceramic Coated Implant (CCI) Evolution Total Ankle Replacements

BACKGROUND

The ceramic coated implant (CCI) Evolution was a third-generation implant design used in approximately 2000 total ankle replacements (TARs) between 2003 and 2016. Because this implant was abandoned, long-term follow-up studies are lacking.

METHODS

All patients undergoing TAR using a CCI prosthesis between 2004 and 2012 were included for analysis. Preoperatively the tibiotalar alignment was measured, and postoperatively the patients were followed up clinically, with radiographs and by questionnaire. The primary outcome was implant survival at 10 years of follow-up. Implant survival was also compared for (1) inflammatory joint disease vs noninflammatory joint disease and (2) preoperative tibiotalar neutral vs varus or valgus alignment. The secondary outcomes were complications, reoperations, and function (assessed by patient-reported outcome measures).

RESULTS

Two hundred fifty-four TARs were performed in 237 patients. Two hundred twelve additional procedures were performed to achieve stable ankles. At 10-year follow-up, the survival was 67.5%, with an average time to revision of 4.5 years. The 10-year survival of the inflammatory joint disease group was 76.8% and of the noninflammatory joint group 63.1% (P = .44). In 248 TARs, the preoperative tibiotalar alignment was measured; (62% neutral, 25% varus, and 13% valgus), these showed 10-year survival rates of 74.7%, 48.2%, and 68.9% respectively (P = .07). The complication rate was 54%; 37% of patients underwent reoperation. At a mean of 8.5 years, postoperative satisfaction scored an average of 7.0 (SD 2.26) on a 0- to 10-point numeric rating scale. The mean Foot and Ankle Ability Measure sports subscore was 24.7, the mean Foot and Ankle Outcome Score (FAOS) sports subscore was 42.8, and the mean 36-Item Short Form Health Survey score was 40.0. Regarding daily activities, the mean FAOS was 81.0.

CONCLUSION

This is currently the sole study reporting the long-term results of the CCI prosthesis. The survival and functional outcomes were inferior to other third-generation mobile-bearing ankle implants.

Home and Outpatient Physical Therapy Utilization Following Total Ankle Replacement

Background

Physical therapy (PT) following total ankle replacement (TAR) is often considered, but guidelines for its use are not standardized. Although patient factors may dictate recommendations, this retrospective cohort study aims to characterize baseline utilization practices to set the stage for establishing generalizable recommendations.

Methods

TAR patients were identified from the 2010-2019 M91 Ortho PearlDiver data set based on administrative coding. Patient factors were extracted, including age, sex, Elixhauser Comorbidity Index (ECI), region of the country in which patients' surgery was performed (Midwest, Northeast, South, West), and insurance plan (commercial, Medicaid, Medicare). The incidence, timing, and frequency of home or outpatient PT utilization in the 90 days following TAR were identified. Inpatient PT was not captured. Univariate and multivariate logistic regression analyses allowed identification of predictive factors for PT utilization.

Results

Of 5412 TAR patients identified, postoperative PT services were used by 2453 (45.3%). Most PT was outpatient (38.3% of the study population) compared to home (4.1% of the study population). Weekly utilization of PT was greatest in the first week following surgery (17.7% of PT visits) and thereafter followed a roughly bell-shaped curve, with utilization greatest at 7 weeks following surgery (14.9% of PT visits).Independent predictors of PT utilization following TAR included having surgery performed in the Midwest (relative to the South, OR 1.37, P < .0001), Northeast (OR 1.20, P = .0217), or West (OR 1.26, P < .0021) and having commercial (relative to Medicare, OR 1.87, P < .0001) or Medicaid insurance (OR 1.46, P = .0239).

Conclusion

Of 5412 TAR patients, 42.5% used PT within 90 days of surgery. PT utilization was highest in the first and seventh weeks following surgery, and demographic predictors of PT use were defined. Through identification of timing and predictors of PT utilization following TAR, PT care pathways may be better defined.

Level of Evidence

Level III, retrospective cohort study.

Medial malleolar osteotomy for the correction of tibiotalar varus deformity during total ankle arthroplasty: Results in 95 ankles

BACKGROUND

The importance of deformity correction before or during total ankle replacement (TAR) has been recognized for a long time. Our results of TAR, combined with medial malleolar lengthening osteotomy, for the reconstruction of osteoarthritic ankles with varus deformity are hereby reported.

METHODS

All ankles in which a medial malleolar osteotomy was performed during implantation of an ankle prosthesis during the period 1998-2018 were filtered out of our database. Preoperative coronal talar alignment was evaluated by measuring the angle between the tibial shaft and talar dome on the weightbearing mortise ankle radiograph. Patient-reported outcomes were measured with the Foot and Ankle Outcome Score (FAOS) and the Foot and Ankle Ability Measure (FAAM). A Kaplan-Meier survival curve was constructed and the number of revisions per 100 observed component years was calculated for interprosthetic comparison.

RESULTS

A total of 95 TARs were included, consisting of the Alpha Ankle Arthroplasty (n = 22); Buechel-Pappas (n = 14) and the Ceramic Coated Implant Evolution (n = 59) prostheses. The preoperative average talar angle in these ankles was 12.4 degrees varus. In 33% (31/95) corrective procedures, in addition to the medial malleolar osteotomy, were performed. A reoperation rate of 44% (42/95) was found, including 28 revisions (revision rate 29% (4% septic; 25% aseptic) at an average follow-up of 5.9 years, resulting in a survival of 0.69 for the total cohort at 10 years of follow-up. At an average follow-up of 6.6 years the average FAOS scores were: FAOS_symptoms 66, FAOS_pain 73, FAOS_function 78, FAOS_sport 45 and FAOS_{quality of life} 56 respectively. The FAAM_adl score averaged 64.

CONCLUSION

This is the largest cohort of TAR combined with medial malleolar osteotomy to date. A 29% revision rate at 5.9 years of average follow-up compares unfavorably with regular cohort studies and with most other results in varus-deformed ankles. Scores on the FAOS and FAAM are comparable to those obtained in regular cohorts with similar length of follow-up. TAR in varus-deformed ankles necessitating medial malleolar osteotomy has an even higher failure rate than regular TAR. Obtaining a stable prosthesis with a neutrally-aligned hindfoot at the end of the procedure is of paramount importance.

LEVEL OF EVIDENCE

IV.

Outcomes of trabecular metal total ankle replacement: a longitudinal observational cohort study of 239 consecutive cases from the Swedish Ankle Registry

BACKGROUND AND PURPOSE

Information on outcomes after some modern total ankle replacement (TAR) designs is scarce. We therefore examined outcomes after trabecular metal (TM) TAR in Sweden by use of data from the national registry.

PATIENTS AND METHODS

On December 31, 2020, 239 primary TM TARs had been reported to the Swedish Ankle Registry. We analyzed prosthesis survival probability, using exchange or permanent extraction of components as endpoint for 239 protheses with mean follow-up of 2.2 years (0.1-6.6), risk of revision, as well as patient-reported outcome measures (SEFAS/EQ-5D/EQ-VAS) and satisfaction with surgery.

RESULTS

7/239 prostheses (3%) had been revised by December 31, 2020. We found an overall prosthesis survival probability of 95% (95% CI 89-98) after 3 years. 2 years after surgery 81% of the answering patients were satisfied or very satisfied with surgery and patients reported median SEFAS 36 (max 48), EQ-5D 0.90 (max 1), and EQ-VAS 80 (max 100).

INTERPRETATION

We found short- to mid-term outcomes after TM TAR to be at least as good as after other TAR designs regarding prosthesis survival and patient-reported satisfaction.

Post-operative management after total ankle arthroplasty: A systematic review of the literature

BACKGROUND

Currently, there is no consensus on the most appropriate post-operative management for patients undergoing total ankle arthroplasty. The aim of this study is therefore to offer a systematic review of the pertaining literature to identify current post-operative protocols and describe possible differences.

METHODS

A systematic review to identify recent studies concerning the post-operative management after total ankle arthroplasty was conducted. Five topics were analyzed: length of hospital stay, type and duration of immobilization, weight-bearing management, post-operative pharmacological therapies, adopted rehabilitation scheme.

RESULTS

Eighty-four studies met the inclusion criteria and were included in the review process. Most of the papers appear to have conflicting opinions with no consensus and homogeneous protocols.

CONCLUSION

Due to various methodological limitations, it is not possible to provide sufficiently supported evidence-based recommendations, and it is therefore difficult to determine the superiority of one post-operative protocol over the others after total ankle arthroplasty.

Preliminary Report of a Hybrid Total Ankle Arthroplasty Combining a Stemmed Intramedullary Tibial Component With Chamfer-Cut Talar Dome

Total ankle arthroplasty (TAA) is a viable treatment for end-stage ankle arthritis. In our experience, a stemmed intramedullary tibial component combined with a chamfer-cut talar component provides the most stable construct for TAA. We present our technique for placement of this hybrid prosthesis utilizing the INBONE tibial component in combination with the INFINITY talar component. This technique differs from the standard protocol by minimizing use of both patient-specific and standard intraoperative guides. The primary aim of this study is to report our preliminary outcomes with our novel technique. Secondarily, we aim to demonstrate that placement of this hybrid prosthesis is radiographically reproducible and accurate. The first 10 patients undergoing this technique with at least 1 year of follow-up were retrospectively reviewed. Average visual analog pain scale decreased from 7.4 preoperatively to 0.5 at 1 year postoperatively. The average time to weightbearing was 6.4 weeks. Complications were minimal, and no implant-related complications were encountered. First weightbearing ankle radiographs postoperatively were evaluated by 3 reviewers to determine accuracy of the tibial intramedullary stem in relation to the anatomical axis of the tibia. We found that the deviation of the tibial implant from the anatomic axis was on average 0.9°± 0.5° in the coronal plane, and 2.2°± 2.7° in the sagittal plane. Inter-rater reliability was 83%. We conclude that this hybrid technique utilizing a stemmed intramedullary tibial component in combination with a chamfer-cut talar component for TAA is reproducible, accurate, and safe.

The INFINITY Total Ankle Prosthesis: Outcomes at Short-Term Follow-up

BACKGROUND

The INFINITY total ankle prothesis remains the most widely used fourth-generation total ankle arthroplasty (TAA) system in the United States. The purpose of the present study was to assess radiographic outcomes for INFINITY at short-term follow-up.

METHODS

All patients who underwent primary TAA with INFINITY between August 2015 and June 2018 at a single institution and who were at least 1 year postoperative were included. A total of 55 ankles with a mean follow up 22 months (range, 12-43 months) met the criteria. Weightbearing radiographs were assessed using coronal and sagittal alignment parameters preoperatively, at 6 to 8 weeks postoperatively, and at the most recent follow-up. Medical records and charts were reviewed and revisions, reoperations, and complications were classified according to the criteria established by Vander Griend et al and Glazebrook at el, respectively.

RESULTS

Overall, INFINITY survivorship was 98.2%. Coronal and sagittal tibiotalar alignment improved after surgery (P < .001, P = .09, respectively), and was maintained during the latest follow-up (P = .62, P = .47, respectively). Only 1 ankle (1.8%) required early revision; while 5 (9.1%) indicated non-implant-related revision; 85.5% required no reoperation. In nineteen ankles (34.5%), postoperative periprosthetic lucency was observed; most were not progressive (17 ankles, 89.5%). Twelve complications (3 high grade, 3 intermediate, and 6 low grade) in 11 ankles (20%) were recorded according to the Glazebrook classification system.

CONCLUSION

INFINITY survivorship was 98.2% at a mean of 1.8 years of follow-up, and only 1 ankle required prosthetic revision. Additional studies with longer follow-up are warranted for fourth-generation TAA prostheses.

LEVELS OF EVIDENCE

Level IV: Case series.

Outcomes and Complications of the INFINITY Total Ankle: A Systematic Review

IV.

Revision Rates After Total Ankle Replacement: A Comparison of Clinical Studies and Arthroplasty Registers

BACKGROUND

The aim of this study was to assess the outcome of total ankle replacement (TAR) regarding revision rates by comparing clinical studies of the last decade to data displayed in arthroplasty registers. The secondary aim was to evaluate whether dependent clinical studies show a superior outcome to independent publications. Additionally, revision rates of mobile bearing implants (MB-TARs) were compared to those of fixed bearing implants (FB-TARs).

METHODS

Clinical studies on TARs between 2010 and 2020 were systematically reviewed, with the endpoint being a revision for any reason. The parameter "revision rate per 100 observed component years (CYs)" was calculated for each publication. The pooled revision rate for clinical studies was compared to the data reported in arthroplasty registers. In a second step, revision rates were subdivided and analyzed for independent and dependent publications and for FB-TARs and MB-TARs.

RESULTS

A total of 43 publications met the inclusion criteria comprising 5806 TARs. A revision rate of 1.8 per 100 observed CYs was calculated, corresponding to a 7-year revision rate of 12.6%. The 3 arthroplasty registers included showed revision rates ranging from 8.2% to 12.3% after 7 years. No significant difference between dependent and independent publications nor between FB-TARs and MB-TARs was detected.

CONCLUSION

Revision rates of clinical studies and arthroplasty registers are comparable. Surgeons can compare their own revision rates with those from this study. Dependent studies do not seem to be biased, and no superiority for one bearing type can be described.

LEVEL OF EVIDENCE

Level III, systematic review of level III studies.

Evaluating and Managing the Painful Total Ankle Replacement

The number of total ankle replacements (TARs) performed in the United States has dramatically increased in the past 2 decades due to improvements in implant design and surgical technique. Yet as the prevalence of TAR increases, so does the likelihood of encountering complications and the need for further surgery. Patients with new-onset or persistent pain after TAR should be approached systematically to identify the cause: infection, fracture, loosening/subsidence, cysts/osteolysis, impingement, and nerve injury. The alignment of the foot and ankle must also be reassessed, as malalignment or adjacent joint pathology can contribute to pain and failure of the implant. Novel advanced imaging techniques, including single-photon emission computed tomography and metal-subtraction magnetic resonance imaging, are useful and accurate in identifying pathology. After the foot and ankle have been evaluated, surgeons can also consider contributing factors such as pathology outside the foot/ankle (eg, in the knee or the spine). Treatment of the painful TAR is dependent on etiology and may include debridement, bone grafting, open reduction and internal fixation, realignment of the foot, revision of the implants, arthrodesis, nerve repair/reconstruction/transplantation surgery, or, in rare cases, below-knee amputation.Level of Evidence: Level V, expert opinion or review.

Analysis of 408 Total Ankle Arthroplasty Adverse Events Reported to the US Food and Drug Administration From 2015 to 2018

Background. Total ankle arthroplasty (TAA) use has increased with newer generation implants. Current reports in the literature regarding complications use data extracted from high-volume centers. The types of complications experienced by lower-volume centers may not be reflected in these reports. The purpose of this study was to determine a comprehensive TAA adverse event profile from a mandatory-reporting regulatory database. Methods. The US Food and Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database was reviewed from 2015 to 2018 to determine reported adverse events for approved implants. Results. Among 408 unique TAA device failures, the most common modes of failure were component loosening (17.9%), intraoperative guide or jig error (15.4%), infection (13.7%), and cyst formation (12.7%). In addition, the percentage distribution of adverse event failure types differed among implants. Conclusion. The MAUDE database is a publicly available method that requires mandatory reporting of approved device adverse events. Using this report, we found general agreement in types of complications reported in the literature, although there were some differences, as well as differences between implants. These data may more accurately reflect a comprehensive profile of TAA complications as data were taken from a database of all device users rather than only high-volume centers.Levels of Evidence: NA.

Two-Year Outcomes After Total Ankle Replacement With a Novel Fixed-Bearing Implant

BACKGROUND

The Integra Cadence total ankle replacement (TAR) is a fourth-generation anatomic, fixed-bearing implant requiring minimal tibial and talar resection, which has been in clinical use since June 2016. The primary purpose of this study is to assess its short-term clinical and radiographic outcomes after TAR using this prosthesis.

METHODS

This is a prospective case series of consecutive patients that underwent TAR using this novel fourth-generation prosthesis between June 2016 and November 2017. The primary outcome of interest was the Ankle Osteoarthritis Scale (AOS). Secondary outcomes included Short Form Health Survey-36 (SF-36) scores, radiographic alignment, complications, reoperations, and revisions.

RESULTS

In total, 69 patients were included in our study. Fifty-one patients (73.9%) required a total of 91 ancillary procedures. Postoperatively, AOS pain scores decreased significantly by an average of 17.8±30.1 points from 45.9±18.2 to 28.4±27.3 (P < .001). AOS disability scores also decreased significantly following surgery by an average of 22.0±30.5 points from 53.9±18.5 to 32.5±27.9 (P < .001). The SF-36 physical component summary score improved 10.4±9.8 points from 33.1±9.1 to 42.6±9.1 (P < .001). Radiographic analysis demonstrated significant improvement to neutral coronal plane alignment, which was achieved in 97% of patients (P < .01) with no cyst formation at 2 years. There was 1 reported complication, 9 reoperations, and no metal or polyethylene component revisions. Overall, the 2-year implant survivorship was 100% in our cohort. Eighteen patients (26.1%) demonstrated fibrous ingrowth of the tibial component. However, outcome scores for these patients did not demonstrate any negative effects.

CONCLUSION

In our hands, this TAR system demonstrated excellent early clinical and radiographic outcomes. Patients reported improved physical health status, pain, and disability in the postoperative period. Total ankle instrumentation allowed for accurate and reproducible implantation with correction of coronal and sagittal plane deformities. Early results for the clinical use of this TAR system are promising, but further long-term prospective outcome studies are necessary.

LEVEL OF EVIDENCE

Level IV, case series.

Early experience and patient-reported outcomes of 503 INFINITY total ankle arthroplasties

AIMS

This is a multicentre, non-inventor, prospective observational study of 503 INFINITY fixed bearing total ankle arthroplasties (TAAs). We report our early experience, complications, and radiological and functional outcomes.

METHODS

Patients were recruited from 11 specialist centres between June 2016 and November 2019. Demographic, radiological, and functional outcome data (Ankle Osteoarthritis Scale, Manchester Oxford Questionnaire, and EuroQol five-dimension five-level score) were collected preoperatively, at six months, one year, and two years. The Canadian Orthopaedic Foot and Ankle Society (COFAS) grading system was used to stratify deformity. Early and late complications and reoperations were recorded as adverse events. Radiographs were assessed for lucencies, cysts, and/or subsidence.

RESULTS

In all, 500 patients reached six-month follow-up, 420 reached one-year follow-up, and 188 reached two-year follow-up. The mean age was 67.8 years (23.9 to 88.5). A total of 38 patients (7.5%) presented with inflammatory arthritis. A total of 101 (20.0%) of implantations used patient-specific instrumentation; 167 patients (33.1%) underwent an additional procedure at the time of surgery. A total of seven patients died of unrelated causes, two withdrew, and one was lost to follow-up. The mean follow-up was 16.2 months (6 to 36). There was a significant improvement from baseline across all functional outcome scores at six months, one, and two years. There was no significant difference in outcomes with the use of patient-specific instrumentation, type of arthritis, or COFAS type. Five (1.0%) implants were revised. The overall complication rate was 8.8%. The non-revision reoperation rate was 1.4%. The 30-day readmission rate was 1.2% and the one-year mortality 0.74%.

CONCLUSION

The early experience and complications reported in this study support the current use of the INFINITY TAA as a safe and effective implant in the treatment of end-stage ankle arthritis. Cite this article: Bone Joint J 2021;103-B(7):1270-1276.

Intermediate-term Patient-Reported Outcomes and Radiographic Evaluation Following Intramedullary- vs Extramedullary-Referenced Total Ankle Replacement

BACKGROUND

The purpose of this study was to report on the radiographic outcomes, clinical outcomes, and implant survivorship following extramedullary-referenced (EMr) vs intramedullary-referenced (IMr) total ankle replacement (TAR).

METHODS

From May 2007 to February 2018, a consecutive series of patients with end-stage tibiotalar osteoarthritis undergoing TAR was enrolled in this study. Analyses were performed comparing IMr vs EMr components for patient-reported outcomes data, pre- and postoperative radiographic ankle alignment, concomitant procedures, and complications. Kaplan-Meier survivorship analyses served to determine implant reoperation and revision surgery. A total of 340 TARs were included with 105 IMr TAR and 235 EMr TAR. The mean follow-up was 5.3 years (±2.5, range 2-12).

RESULTS

The absolute value for preoperative coronal alignment was significantly greater for IMr compared to EMr TAR (13.0 vs 6.4 degrees; P < .0001), but both groups achieved near neutral alignment postoperatively (1.4 vs 1.5 degrees; P = .6655). The odds of having a concomitant procedure was 2.7 times higher in patients with an IMr TAR (OR 2.7, CI 1.7-4.4; P < .0001). There were similar improvements in patient-reported outcome scores at 1 year and final follow-up (all P > .05). The 5-year implant survivorship was 98.6% for IMr vs 97.5% for EMr at final follow-up.

CONCLUSION

The IMr and EMr TAR components had comparable postoperative alignment, patient-reported outcome scores, and complications. The 5-year implant survivorship was similar between the IMr and EMr groups.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Achilles tendon moment arm changes with total ankle arthroplasty

Prior research on total ankle arthroplasty (TAA) has focused on improvements in pain and function following the surgical treatment of ankle arthritis, but its effect on ankle joint mechanics has received relatively little attention. The plantarflexion moment arm of the Achilles tendon is a critical determinant of ankle function with the potential to be altered by TAA. Here we investigate the effect of TAA on Achilles tendon moment arm assessed using two methods. Standing sagittal-plane radiographs were obtained for ten patients presurgery and postsurgery, from which anterior-posterior distance between the posterior calcaneus and the center of the talar dome was measured. Ultrasound imaging and three-dimensional (3D) motion capture were used to obtain moment arm pre- and post-TAA. The absolute changes in moment arm pre- to post-TAA were significantly different from zero for both methods (9.6 mm from ultrasound and 4.6% of the calcaneus length from radiographs). Only 46% of the variance in postoperative 3D Achilles tendon moment arm was explained by the preoperative value (r²  = 0.460; p = .031), while pre- and post-TAA values from radiographs were not correlated (r²  = 0.192, p = .206). While we did not find significant mean differences in Achilles tendon moment arm between pre- and post-TAA, we did find absolute changes in 3D moment arm that were significantly different from zero and these changes were partially explained by a change in location of the talar dome as indicated by measurements from radiographs (r²  = 0.497, p = .023).

Biomechanical evaluation of total ankle arthroplasty. Part II: Influence of loading and fixation design on tibial bone-implant interaction

Finite element (FE) models to evaluate the burden placed on the interaction between total ankle arthroplasty (TAA) implants and the bone often rely on peak axial forces. However, the loading environment of the ankle is complex, and it is unclear whether peak axial forces represent a challenging scenario for the interaction between the implant and the bone. Our goal was to determine how the loads and the design of the fixation of the tibial component of TAA impact the interaction between the implant and the bone. To this end, we developed a framework that integrated robotic cadaveric simulations to determine the ankle kinematics, musculoskeletal models to determine the ankle joint loads, and FE models to evaluate the interaction between TAA and the bone. We compared the bone-implant micromotion and the risk of bone failure of three common fixation designs for the tibial component of TAA: spikes, a stem, and a keel. We found that the most critical conditions for the interaction between the implant and the bone were dependent on the specimen and the fixation design, but always involved submaximal forces and large moments. We also found that while the fixation design influenced the distribution and the peak value of bone-implant micromotion, the amount of bone at risk of failure was specimen dependent. To account for the most critical conditions for the interaction between the implant and the bone, our results support simulating multiple specimens under complex loading profiles that include multiaxial moments and span entire activity cycles.

Economic Analysis and Clinical Outcomes of Short-Stay Versus Inpatient Total Ankle Replacement Surgery

BACKGROUND

We aimed to perform an economic analysis and compare the clinical outcomes between inpatient and short-stay designation total ankle replacement (TAR).

METHODS

We performed a retrospective study on 178 consecutive patients undergoing primary inpatient versus short-stay designation TAR during the 2016 and 2017 fiscal years. Patient demographics, concomitant procedures, perioperative complications, patient-reported outcomes, and perioperative costs were collected.

RESULTS

The mean age of our cohort was 62.5 ± 9.6 years (range, 30-88 years), with a significant difference in age (64.1 vs 58.5 years) (P = .005) and Charlson Comorbidity Index (3.3 ± 1.9 vs 2.3 ± 1.4; P = .002) for the inpatient and short-stay designation groups, respectively. At a mean follow-up of 29.6 ± 11.8 months (range, 12-52.3 months), there was no difference in complications between groups (P = .97). The inpatient designation TAR group had a worse baseline Short Musculoskeletal Functional Assessment (SMFA) function score (76.1; 95% CI, 70.5-81.6) than the short-stay designation TAR group (63.9; 95% CI, 52.5-75.3) while achieving similar final postoperative SMFA function scores for the inpatient (55.2; 95% CI, 51.1-59.2) and short-stay (56.2; 95% CI, 48.2-64.2) designation TAR groups (P > .05). However, the inpatient designation TAR group showed a significantly greater mean improvement in SMFA function score (20.9; 95% CI, 19.4-22.4) compared with the short-stay designation TAR group (7.7; 95% CI, 3.7-11.1) (P = .0442). The total direct cost was significantly higher for the inpatient designation group ($15 340) than the short-stay designation group ($13 002) (P < .001).

CONCLUSION

While inpatient designation TARs were more comorbid, short-stay designation TARs were associated with a 15.5% reduction in perioperative costs, comparable complication rates, and similar final postoperative patient-reported outcome scores compared with inpatient TARs.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Infinity ankle arthroplasty with traditional instrumentation and PSI prophecy system: preliminary results

Ankle arthrodesis has been considered the surgical Gold Standard for advanced ankle arthritis; prosthetic replacement of the tibio-talar joint played a secondary role.The introduction of last generation ankle prostheses lead to better outcome and a lower rate of complication. PSI represents the most recent innovations introduced on the market of ankle arthroplasty:PSI is proposed as a surgical technique capable of making ankle arthroplasty more accurate and more reproducible compared to standard referencing guides Aim of the study is to report early clinical and radiographic outcomes obtained from a single surgeon experience by implanting the same ankle prosthesis using a standard (STD) or a PSI instrumentation Unlike no difference in the average increment of normalized sub score related to function in each group (PSI vs STD), the analysis of normalized pain sub score pointed out a greater average improvement in the PSI group(+75%)compared to the STD group(+62%);this result has been adovacated to the absence of post operative gutter impingement syndrome in the PSI group compared to the STD referencing group. The analysis of radiographic angles revealed a more accurate and reproducible positioning of the components in the PSI group; ankle arthroplasty performed with PSI reported a reduction of both surgical times and the need of intraop.fluoroscopy. PSI ankle arthroplasty achived more accurate and reproducible clinical and radiographic results compared to STD instrumentation;long-term follow-up are needed to demonstrate whether a better positioning of the implant is associated with an increased survival of the prosthesis and therefore justifies the additional costs of PSI.

Ankle Arthritis

Ankle arthritis is a major source of morbidity impacting a younger working age population than hip and knee arthritis. Unlike the hip and knee, more than 70% of ankle arthritis cases are post-traumatic, with the remainder being inflammatory or primary arthritis. Nonoperative treatment begins with lifestyle and shoe-wear modifications and progresses to bracing, physical therapy, anti-inflammatory medications, and intra-articular injections. Ankle arthrodesis and total ankle arthroplasty are the 2 main surgical options for end-stage ankle arthritis, with debridement, realignment osteotomy, and distraction arthroplasty being appropriate for limited indications.

Increased Early Revision Rate With the INFINITY Total Ankle Prosthesis

BACKGROUND:

A number of new 2-component total ankle arthroplasty systems that emphasize minimal bone resection have been introduced for which few clinical outcomes reports are available. Our aim was to identify the rate of early revision among patients receiving the 2-component INFINITY prosthesis.

METHODS:

Patients from 2 prospectively collected databases at the authors' institution were screened for inclusion in the present study. All patients who underwent a primary total ankle arthroplasty (TAA) with the INFINITY prosthesis and who were at least 1 year postoperative were included. A total of 159 ankles with a mean 20 months of follow up (range, 12-37) met these criteria. All surgeries were performed by 1 of 2 orthopedic foot and ankle surgeons with extensive experience in TAA. The primary outcome was the need for revision surgery, defined as removal of 1 or both metal components. Peri-implant lucency at most recent follow-up was a secondary outcome. Weightbearing radiographs at most recent follow-up were graded for lucency independently by 2 reviewers.

RESULTS:

Sixteen ankles (10%) underwent revision at a mean 13 months postoperatively. The most common reasons for revision were symptomatic tibial component loosening and deep infection (6 patients each, 3.8%). Of the 108 ankles with retained components and at least 1 year of radiographic follow-up, 8 (7.4%) had global lucency around the tibial component suggestive of loosening at most recent follow-up.

CONCLUSIONS:

Our initial review of patients undergoing TAA with this new 2-component prosthesis demonstrates an elevated early revision rate due to tibial component loosening compared to other implant systems.

LEVEL OF EVIDENCE:

Level IV, case series.