Midterm Results of the Salto Talaris Total Ankle Arthroplasty

Design Rational for Total Ankle Arthroplasty: An Update

The design of total ankle arthroplasty (TAA) systems is rapidly evolving as device companies try to keep pace with the expansion of surgical indications and a refinement of techniques for TAA. Even since the publication of the latest "update," published in 2018, three new designs and three updates on preexisting third-generation implants came onto the market. Improvements in third-generation TAA systems include minimal bone resection, retaining ligamentous support, and anatomic balancing. Fourth-generation systems use 3D printing technology, improved talus and tibia designs based on CT scans of arthritic and normal ankles, and include patient-specific instrumentation. We will then explore the short-term and mid-term outcomes of the previously discussed six TAA systems-INBONE, INFINITY, INVISION (Stryker), Salto-Talaris (Smith and Nephew), Scandinavian Total Ankle Arthroplasty (Enovis), Trabecular Metal Total Ankle (Zimmer Biomet), and VANTAGE (Exactech). As more research pours in regarding mid- to long-term outcomes of these implants, it is important to assess the design rationale and summarize current outcome data for these implants.

Outcomes of Total Ankle Replacement

Total ankle replacement (TAR) is an effective operative treatment of end-stage ankle osteoarthritis (OA) in the appropriate patient, conferring improved kinematic function, decreased stress across adjacent joints, and offering equivalent pain relief in comparison to ankle arthrodesis (AA). It is important to consider patient age, weight, coronal tibiotalar deformity, joint line height, and adjacent joint OA to maximize clinical and patient outcomes. Both mobile-bearing and fixed-bearing implants have demonstrated favorable clinical outcomes, marked improvement in patient-reported outcomes, and good survivorship; however, implant survivorship decreases with longer term follow-up, necessitating constant improvement of primary and revision TAR options.

Outcome after total ankle replacement or ankle arthrodesis in end-stage ankle osteoarthritis on the basis of german-wide data: a retrospective comparative study over 10 years

BACKGROUND

In symptomatic end-stage osteoarthritis of the ankle joint, total ankle replacement and ankle arthrodesis are the two primary surgical options for patients for whom conservative treatment fails. Published revision rates are often biased and difficult to compare. In this study, unplanned reoperation rates and revision rates were determined for both surgical interventions based on a large dataset, and risk factors for unplanned reoperations were identified.

METHODS

German-wide health data of the largest German health-care insurance carrier between 2001 and 2012 were retrospectively analyzed, and unplanned reoperation rates within 10 years were determined for index surgeries conducted in 2001 and 2002. Unplanned reoperation rates within 5 years for index surgeries conducted in 2001/2002 were compared to index surgeries conducted in 2006/2007. Multivariate logistic regression was used to identify risk factors for unplanned reoperations.

RESULTS

After ankle arthrodesis, 19% (95% confidence interval [CI], 16-22%) of 741 patients needed to undergo an unplanned reoperation within ten years. After total ankle replacement, the unplanned reoperation rate was 38% [95% CI, 29-48%] among 172 patients. For initial surgeries conducted at a later date, unplanned reoperation rates within five years were 21% [95% CI, 19-24%] for 1,168 ankle arthrodesis patients and 23% [95% CI, 19-28%] for 561 total ankle replacement patients. Significant risk factors for unplanned reoperations after ankle arthrodesis in the initial cohort were age < 50 years (odds ratio [OR] = 4.65 [95% CI 1.10;19.56]) and osteoporosis (OR = 3.72 [95% CI, 1.06;13.11]); after total ankle replacement, they were osteoporosis (OR = 2.96 [95% CI, 1.65;5.31]), Patient Clinical Complexity Level (PCCL) grade 3 (OR = 2.19 [95% CI, 1.19;4.03]), PCCL grade 4 (OR = 2.51 [95% CI, 1.22;5.17]) and diabetes mellitus (OR = 2.48 [95% CI, 1.33;4.66]). Kaplan-Meier analyses including 1,525 ankle arthrodesis patients and 644 total ankle replacement patients revealed an average unplanned reoperation-free time of approximately 17 years for both procedures.

CONCLUSIONS

Similar revision rates and unplanned reoperation rates for both procedures in the later-date cohort can likely be attributed to a learning curve for surgeons as well as advances in implant design. This analysis of billing health insurance data supports an increase in total ankle replacement surgeries.

Artificial Intelligence Language Models Are Useful Tools for Patients Undergoing Total Ankle Replacement

Background

Artificial intelligence (AI) large language models (LLMs), such as Chat Generative Pre-trained Transformer (ChatGPT), have gained traction as both augmentative tools in patient care but also as powerful synthesizing machines. The use of ChatGPT in orthopaedic foot and ankle surgery, particularly as an informative resource for patients, has not been described to date. The purpose of this study was to assess the quality of information provided by ChatGPT in response to commonly asked questions about total ankle replacement (TAR).

Methods

ChatGPT was asked 10 frequently asked questions about TAR in a conversational thread. Responses were recorded without follow-up, and subsequently graded A, B, C, or F, corresponding with “excellent response,” “adequate response needing mild clarification,” “inadequate response needing moderate clarification,” and “poor response needing severe clarification.”

Results

Of the 10 responses, 2 were grade “A,” 6 were grade “B,” 2 were grade “C,” and none were grade “F.” Overall, the LLM provided good-quality responses to the posed prompts. Conclusion. Overall, the provided responses were understandable and representative of the current literature surrounding TAR. This study highlights the potential role LLMs in augmenting patient understanding of foot and ankle operative procedures.

Levels of Evidence:

IV.

Salto Talaris Fixed-Bearing Total Ankle Arthroplasty: Long-Term Results at a Mean of 10.7 Years

Background

Total ankle arthroplasty (TAA) has become increasingly popular in the treatment for end-stage ankle arthritis in recent decades. However, there is limited evidence regarding the long-term clinical outcomes and complication rates of modern TAA implants.

Methods

This study presents a follow-up on a previous cohort involving 78 patients (81 ankles) who underwent Salto Talaris fixed-bearing TAA to treat end-stage arthritis, with a mean postoperative follow-up of 5.2 years. The aim of this follow-up study was to assess the radiographic (33 patients, 35 ankles) and clinical (48 patients, 50 ankles) results from the original cohort at a mean of 10.7 years (range, 7.8-14 years).

Results

At a mean of 10.7 years, the Kaplan-Meier estimated survivorship was 84.2% (95% CI, 71.9%-98.6%). For the patients reviewed, we did not find any change in patient-reported outcomes between an average 5- and 11-year follow-up. Measured total range of motion and plantarflexion did not change between 1 and 11 years, but dorsiflexion was measured as decreasing by an average of 4 degrees (P < .02).

Conclusion

In this longer-term follow-up of a limited cohort, we found that Salto Talaris fixed-bearing TAA demonstrated good long-term survival with relatively low rates of revision or other complications. Patient-reported outcome and range of motion measures revealed good stability.

Level of Evidence

Level III, therapeutic.

Survival and risk assessment in revision arthroplasty of the ankle

Aims

Implant failure has become more common as the number of primary total ankle arthroplasties (TAAs) performed has increased. Although revision arthroplasty has gained attention for functional preservation, the long-term results remain unclear. This study aimed to assess the long-term outcomes of revision TAA using a mobile-bearing prosthesis in a considerably large cohort; the risk factors for failure were also determined.

Methods

This single-centre retrospective cohort study included 116 patients (117 ankles) who underwent revision TAA for failed primary TAA between July 2000 and March 2010. Survival analysis and risk factor assessment were performed, and clinical performance and patient satisfaction were evaluated preoperatively and at last follow-up.

Results

The mean duration from initial revision TAA to last follow-up was 15.0 years (SD 3.0; 11.2 to 20.5). The cumulative survival rates of the revised ankles were 81% (95% confidence interval (CI) 74% to 88%), 74% (65% to 82%), and 70% (61% to 79%) at five, ten, and 15 years, respectively. Comorbidities prior to primary TAA, aseptic loosening, instability, or grafting of cysts were found to be the most common risk factors for secondary revision. The median value for preoperative pain, as assessed using the visual analogue scale, declined from 6 (interquartile range (IQR) 5 to 8) to 2 (IQR 0 to 5) (p < 0.001) and the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 43 (SD 17) preoperatively to 70 (SD 20) (p < 0.001) at last follow-up.

Conclusion

Revision TAA offers acceptable survival rates after 15 years; it therefore offers a valuable option for treatment of implant failure in carefully selected cases. Although patient-reported outcomes improve substantially, the degree of improvement reported following primary TAA is not achieved.

Prospective Multicenter Study of Salto Talaris Ankle Arthroplasty With Minimum 4-Year Follow-Up

BACKGROUND

Total ankle arthroplasty (TAA) continues to be investigated as a primary treatment for end-stage ankle arthritis. The objective of this study is to report mid- to long-term results of the Salto Talaris TAA using prospectively collected patient-reported outcomes and implant survival rates with 4- to 13-year follow-up.

METHODS

This was a retrospective study of prospectively collected data from 2 multicenter cohort studies from 3 centers. Three hundred fourteen subjects who received a Salto Talaris TAA from 2005 to 2015 were included in the study. Follow-up ranged 4-13 years following index procedure. Outcomes included 36-Item Short Form Health Survey (SF-36) mental and physical component summary scores, pain scores, and adverse events including additional surgeries, revision, or removal of components.

RESULTS

Significant improvements were seen in pain and physical function scores at 2-year follow-up and were generally maintained through most recent follow-up. The survival rate of the prosthesis was >95% (n = 30/32 at >10 years, n = 272/282 at 4.5-10 years). Thirteen patients (4.1%) underwent revision or removal of their prosthesis. Time to revision ranged from 2 months to 6.5 years following the index procedure. Twenty-two patients (7.0%) had additional surgery that did not involve revision or removal of components.

CONCLUSION

Treatment of end-stage ankle arthritis with this implant provided patients with improved pain and functional outcome scores at mid- to long-term follow-up. The significant improvements reported at 2-4 years appeared to endure through the extended follow-up period.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Talar component subsidence correlates with periprosthetic osteolysis after total ankle arthroplasty

PURPOSE

This study aimed to investigate the relationship between periprosthetic osteolysis around the talar component and the amount of talar component subsidence after total ankle arthroplasty (TAA).

METHODS

This study included forty patients who underwent TAA with a mean follow-up of 67.5 ± 17.0 months. The patients were divided into two groups based on the amount of osteolysis around the talar component, as measured by computed tomography at the latest clinic visit: none to 2 mm (N group, n = 20) and greater than or equal to 2 mm (O group, n = 20). The average amount of talar component subsidence, clinical outcomes, and complications were compared between the two groups. In the O group, the correlation between osteolysis and talar component subsidence was evaluated.

RESULTS

The average talar component subsidence was significantly different between the N (0.22 ± 0.94 mm) and O groups (2.12 ± 2.28 mm). Five out of 20 ankles in the O group required revision surgery owing to talar component subsidence. The Japanese Society for Surgery of the Foot scores in the N and O groups were significantly different: 93.5 ± 7.7 and 85.3 ± 15.4, respectively. In the O group, we found that osteolysis tended to develop on the lateral side, and the amount of osteolysis was positively correlated with the talar component subsidence (r = 0.59, P = .007).

CONCLUSION

In the O group, a positive correlation between osteolysis and talar component subsidence was found, and five patients required revision surgery.

How Does a Novel In Situ Fixed-bearing Implant Design Perform in Revision Ankle Arthroplasty in the Short Term? A Survival, Clinical, and Radiologic Analysis

BACKGROUND

Given the growing number of primary total ankle replacements (TAR), an increase in the number of patients undergoing subsequent revisions might be expected. Achieving a stable and balanced ankle while preserving the remaining bone stock as much as possible is crucial for success in revision TAR. Most reported techniques rely on bulky implants with extended fixation features. Since 2018, we have used a novel, three-component ankle prosthesis for revision that is converted in situ to a fixed-bearing, two-component ankle prosthesis once the components have found their position according to an individual's anatomy. The results of this novel concept (fixation, revision, pain, or function) have not, to our knowledge, been reported.

QUESTIONS/PURPOSES

What are the short-term results with this new revision TAR design, in terms of (1) repeat revision surgery, (2) patient-reported outcomes on the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, (3) pain according to the VAS, and (4) radiographic signs of fixation?

METHODS

Between February 2018 and February 2020, we performed 230 TAR surgeries (in 206 patients) for any indication in our clinic. The novel semiconstrained, uncemented Hintermann Series H2 © implant was used in 96% (220 of 230) of procedures (201 patients). Fifty-four percent (119 of 220) of these were converted from an existing TAR to H2, which was the focus of the present study. However, only 45% (54 of 119) of these conversions to H2 were eligible for analysis. These patients had a mean age of 63 ± 12 years, and 43% (23 of 54) were women. The median (range) follow-up time was 3.2 years (2.0 to 4.3). The H2 design allows in situ conversion to a fixed-bearing system, with minimal bone resection. It achieves translational and rotational stability while preserving function and supporting the periarticular soft tissues. We defined repeat revision as exchange of one or both metal components, ankle fusion, or amputation and assessed it using a cumulative incidence survivorship estimator. Factors potentially associated with revision were assessed using Cox regression analyses. Clinical and radiologic outcomes were assessed preoperatively and at the most recent follow-up interval. Clinical outcomes included pain on the VAS (average pain during normal daily activity during the past seven days) and AOFAS score. Radiologic outcomes were the tibial articular surface angle, tibiotalar surface angle, talar tilt angle in the coronal plane, and AP offset ratio in the sagittal plane, as well as radiolucent lines and radiographic signs of loosening, defined as change in position greater than 2° of the flat base of the tibia component in relation to the long axis of the tibia, subsidence of the talar component into the talus greater than 5 mm, or change in position greater than 5° relative to a line drawn from the top of the talonavicular joint to the tuberosity of the calcaneus, as seen on plain weightbearing radiographs.

RESULTS

The cumulative incidence of repeat revision after 1 and 2 years was 5.6% (95% CI 0% to 11%) and 7.4% (95% CI 0% to 14%), respectively. With the numbers available, no clinical factors we analyzed were associated with the risk of repeat revision. The median values of all assessed clinical outcomes improved; however, not all patients improved by clinically important margins. The median (range) AOFAS ankle-hindfoot score increased (from 50 [16 to 94] to 78 [19 to 100], difference of medians 28; p < 0.01), and the median pain on the VAS decreased (from 5 [0 to 9] to 2 [0 to 9], difference of medians 3; p < 0.01) from before surgery to follow-up at a minimum of 2 years. Radiographically, lucency was seen in 12% (6 of 49 patients) and loosening was seen in 8% (4 of 49). One of these patients showed symptomatic loosening and was among the four patients overall who underwent revision. We could not assess risk factors for repeat revision because of the low number of events (four).

CONCLUSION

The investigated new in situ fixed-bearing ankle design achieved overall better short-term results than those reported in previous research. Destabilization of the ankle joint complex, soft tissue insufficiency, and possible changes of the joint configuration need an optimal solution in revision arthroplasty. The studied implant might be the answer to this complex issue and help surgeons in the perioperative decision-making process. However, a relatively high percentage of patients did not achieve a clinically important difference. Observational studies are needed to understand long-term implant behavior and possibly to identify ankles benefiting the most from revision.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

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.

Complications after total ankle arthroplasty- A systematic review

BACKGROUND

Total ankle arthroplasty was developed as an alternative option to ankle arthrodesis in patients with end-stage ankle osteoarthritis. Multiple trials have assessed the outcomes of ankle arthroplasty, but complication risk or relative effectiveness is not systematized in literature.

AIM

Review complications of new designs of total ankle arthroplasty and the relationship between their severity and failure rates.

METHODS

We reviewed complications and revision rates of prospective studies of primary total ankle arthroplasty that included more than 50 patients and with minimum 2 years follow-up.

RESULTS

We included 22 studies (4412 ankles, median age of 61.9 years) with an adjusted mean follow-up time of 66.6 ± 40.9 months. The adjusted mean complication rate was 23.7 % (2.4-52 %), mostly high-grade complications (35.6 %). We found a statistically significant positive correlation between high- and medium-grade complications and revision rates.

CONCLUSION

Patient selection is crucial to successfully treat end-stage ankle osteoarthritis. Further multicenter clinical trials with consistent reporting of complications are warranted.

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.

Retrospective Comparison of Midterm Survivorship, Radiographic, and Clinical Outcomes of the INBONE II and Salto Talaris Total Ankle Arthroplasty Systems

BACKGROUND

Prior studies on the INBONE II and Salto Talaris total ankle arthroplasty (TAA) systems have reported promising outcomes for both implants. This retrospective study aimed to compare the midterm differences between INBONE II and Salto Talaris TAA.

METHODS

Between 2007 and 2015, a total of 44 INBONE II consecutive cases and 85 Salto Talaris consecutive cases had minimum 5-year clinical and radiographic follow-up. Preoperative and midterm survivorship, postoperative Foot and Ankle Outcome Score (FAOS), and radiographic measures including tibiotalar alignment (TTA), medial distal tibial angle (MDTA), and sagittal tibial angle (STA) were compared.

RESULTS

Survivorship to revision was 97.6% (95% CI, 93.1%-100%) for the INBONE II group and 97% (95% CI, 93%-100%) for the Salto Talaris group (P = .93). Survivorship to reoperation was significantly different: 95.5% for the INBONE II and 76.4% for Salto Talaris (P = .021). Postoperative FAOS pain (P = .01), symptoms (P = .004), and sports activity (P = .02) scores were significantly higher in the INBONE II group. The INBONE group had greater preoperative deformity (varus TTA P < .001, valgus TTA P = .02, valgus MDTA P = .005).

CONCLUSION

Although both implants had similar longevity and postoperative alignment, the INBONE II resulted in greater clinical improvement and fewer reoperations than the Salto Talaris at midterm follow-up.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Intermediate to Long-Term Follow-up of the Salto Talaris Fixed-Bearing Total Ankle Prosthesis

BACKGROUND

Total ankle arthroplasty (TAA) remains a viable option for recalcitrant, end-stage ankle arthritis. Among the various Food and Drug Administration (FDA)-approved prosthetic options is the fixed-bearing Salto Talaris implant. The aim of the present study was to evaluate the intermediate to long-term clinical outcomes and radiographic complications following implantation of the Salto Talaris TAA.

METHODS

Nineteen Salto Talaris total ankle implants were included in the present retrospective study. Medical records were reviewed to determine pre- and postoperative visual analog scale (VAS) pain scores, and both medical records and radiographs were utilized to assess for complications. Telephone interviews were then conducted to assess for overall patient satisfaction.

RESULTS

At a mean follow of 6.9 years (range, 3.5-12 years), there was a 21% complication rate according to the classification system described by Glazebrook et al. The reoperation rate was low at 10.5%, and there was 100% survivorship of the total ankle implant. The average pain decreased from 9.1 (range, 7-10) preoperatively to 2.6 (range, 0-10) postoperatively. Patients reported a 95% satisfaction rate, and 16% of patients reported using a brace postoperatively.

CONCLUSION

The Salto Talaris arthroplasty was associated with low complication and reoperation rates, and a high survivorship at intermediate to long-term follow-up.

LEVELS OF EVIDENCE

4.

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

BACKGROUND AND OBJECTIVE

Loosening 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.

METHODS

This 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.

RESULTS

The 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.

CONCLUSIONS

The 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.

Knee Kinetics and Kinematics in Patients With Ankle Arthroplasty and Ankle Arthrodesis

Background: Previous literature suggests that patients treated with total ankle arthroplasty (TAA) versus ankle arthrodesis (AA) may have better function and lower risk for adjacent joint arthritis in the foot. Little is known on how these interventions affect proximal joints such as the knee. Questions: We sought to assess whether patients with TAA and AA exhibited altered biomechanics linked to the onset and progression of knee osteoarthritis (KOA). We used the knee adduction moment (KAM), a surrogate measure for the mechanical load experienced at the medial tibiofemoral compartment, because it is linked with the onset and progression of KOA. Methods: At a minimum of 2 years postoperatively, instrumented 3-dimensional walking gait was recorded in 10 TAA and 10 AA patients at self-selected walking speeds. TAA patients had either a Salto Talaris or INBONE prosthesis. Average first and second peak KAMs (Nm/kg), KAM impulse (Nm-s/kg), and range-of-motion (ROM, °) were calculated on both the affected and unaffected limbs for each patient. Results: There were no significant differences in the KAM's first and second peaks, impulse, or knee ROM in any plane between the unaffected and affected limbs, or between TAA and AA. Conclusion: TAA and AA may not meaningfully affect ipsilateral knee kinetics and KAMs in short-term follow-up. This study highlights the importance of continuing to study these parameters in larger cohorts of patients with longer follow-up to determine how our treatment of end-stage ankle arthritis may affect the incidence or progression of ipsilateral KOA.

Total Ankle Arthroplasty Can Be Safely and Effectively Performed in the Community Hospital Setting: A Case Series of 65 Patients

The use of total ankle arthroplasty has expanded over the past decade, primarily due to improvements in implant design and survivorship that have significantly reduced the high failure rates observed in first-generation implants. A retrospective review of 65 consecutive patients undergoing primary total ankle arthroplasty with a single senior orthopedic surgeon in a community hospital from January 2014 to December 2019 was performed. All procedures were performed for end stage osteoarthritis, with the most common secondary diagnoses being Achilles contracture (23%), retained hardware (17%) and calcaneovalgus deformity (11%). Preoperatively, patients averaged 10.45 ̊ ± 10.00 ̊ of non-weightbearing dorsiflexion and 30.00 ̊ ± 8.79 ̊ of plantarflexion. Postoperatively, patients averaged 13.33 ̊ ± 7.62 ̊ dorsiflexion, and 25.48 ̊ ± 7.87 ̊ of plantarflexion. A total of 8 (12.3%) patients required reoperation, and average time to reoperation was 1.55 ± 1.58 years. Implant failure, defined as reoperation requiring prosthesis removal, occurred in 2 (3.1%) patients, with an average time to failure of 342 days (105 days in failure due to periprosthetic joint infection and 582 days in failure due to subsidence). Patients undergoing total ankle arthroplasty at our institution had a 12.3% reoperation rate, and a 96.9% implant survival rate over an average follow-up period of 2.42 years, results that compare favorably with previously reported outcomes. Based on these findings, we suggest that this procedure, which is often offered only in academic tertiary care facilities, can be safely and effectively performed by experienced surgeons in the community hospital setting.

Risk Stratification for Revision Surgery Following Total Ankle Replacement

As a result of improved implants total ankle replacement (TAR) is becoming a more reliable option for end stage ankle arthritis. As with any surgery there are numerous complications that can occur intraoperatively and postoperatively with TAR. The primary aim of this study is to use recent data on implants currently on the market to develop a well-defined and comprehensive complication classification system which stratifies risk of subsequent surgery for TAR. A systematic review of studies on TARs from 2013 to 2018 was performed. Inclusion criteria were studies published between 2013 and August 2018, studies having at least 20 patients, data with at least 1-year follow-up and use of implants currently on the market. Studies were excluded if they involved revision cases, case reports, basic science articles and studies published in non-peer-reviewed journals. Sixteen studies fit inclusion criteria involving 3,305 implants. Overall survival of all implants was found to be 93% with a pooled complication rate of 75.6% using criteria for classifying complications by Glazebrook et al. Previously published classification systems did not clearly define complication categories leading to inconsistency in complication reporting and inaccurate complication rates. There are also several complications that are unclassifiable with the classifications developed by Gadd et al and Glazebrook et al. Our proposed updated classification system provides more inclusive tier profiles to capture the complications that can occur with implants currently on the market. Furthermore, this system provides a stratification of risk that these complications pose to ultimate procedure success.

Superiority of upper ankle arthrodesis over total ankle replacement in the treatment of end-stage posttraumatic ankle arthrosis

PURPOSE

Surgical treatment of end-stage posttraumatic upper ankle arthrosis is challenging. Highly variable revision rates have been reported with total ankle arthroplasty (TAA) of the upper ankle joint. The aim of this retrospective study was to compare revision rates with tibiotalar arthrodesis (TTA) and TAA with a prosthesis to determine the superior treatment approach.

METHODS

Data for 148 patients (96 males and 52 females) with end-stage posttraumatic upper ankle arthrosis-including 88 treated with TTA and 60 with TAA between 2008 and 2013, with a mean follow-up of 59 months-were analysed. Bone fusion was confirmed by x-ray radiography and computed tomography.

RESULTS

The overall revision rate was 28%; the rate was higher with TAA (42%) than with TTA (18%). The TAA group showed an increase in revisions from 12- to 24-month postsurgery. The most common cause of revision in the TAA group was cysts (20%), and the most frequent reason for revision was nonunion (8%). Mean American Orthopaedic Foot and Ankle Society (AOFAS) and Foot and Ankle Outcome (FAO) scores in all patients were 55.5 and 53.1, respectively, with no significant difference between the TTA and TAA groups (p > 0.05). In nine cases (15%) the prosthesis was explanted or converted to TTA. TAA patients who underwent conversion to TTA had worse outcomes (AOFAS score = 39; FAO score = 35.29).

CONCLUSION

TAA is associated with a high rate of revisions, especially from the 2nd year postsurgery. Therefore, TTA is the treatment of choice for end-stage posttraumatic upper ankle arthrosis. Level of evidence Level III, comparative 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.

Three-Year Rates of Reoperation and Revision Following Mobile Versus Fixed-Bearing Total Ankle Arthroplasty: A Cohort of 302 Patients with 2 Implants of Similar Design

BACKGROUND

Currently, the implants utilized in total ankle arthroplasty (TAA) are divided between mobile-bearing 3-component and fixed-bearing 2-component designs. The literature evaluating the influence of this mobility difference on implant survival is sparse. The purpose of the present study was therefore to compare the short-term survival of 2 implants of similar design from the same manufacturer, surgically implanted by the same surgeons, in fixed-bearing or mobile-bearing versions.

METHODS

All patients were enrolled who underwent TAA with either the mobile-bearing Salto (Tornier and Integra) or the fixed-bearing Salto Talaris (Integra) in 3 centers by 2 surgeons between January 2004 and March 2018. All patients who underwent TAA from January 2004 to April 2013 received the Salto implant, and all patients who underwent TAA after November 2012 received the Salto Talaris implant. The primary outcome was time, within 3 years, to first all-cause reoperation, revision of any metal component, and revision of any component, including the polyethylene insert. Secondary outcomes included the frequency, cause, and type of reoperation.

RESULTS

A total of 302 consecutive patients were included, of whom 171 received the mobile-bearing and 131 received the fixed-bearing implant. The adjusted hazard ratio for all-cause reoperation was 1.42 (95% confidence interval [CI], 0.67 to 3.00; p = 0.36); for component revision, 3.31 (95% CI, 0.93 to 11.79; p = 0.06); and for metal component revision, 2.78 (95% CI, 0.58 to 13.33; p = 0.20). A total of 31 reoperations were performed in the mobile-bearing group compared with 14 in the fixed-bearing group (p = 0.07). More extensive reoperation procedures were performed in the mobile-bearing group.

CONCLUSIONS

With the largest comparison of 2 implants of similar design from the same manufacturer, the present study supports the use of a fixed-bearing design in terms of short-term failure. We found a 3-times higher rate of revision among mobile-bearing implants compared with fixed-bearing implants at 3 years after TAA. Reoperations, including first and subsequent procedures, tended to be less common and the causes and types of reoperations less extensive among fixed-bearing implants.

LEVEL OF EVIDENCE

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

Investigation on the contour and bone mineral density of the distal tibial cutting surface used for total ankle arthroplasty

PURPOSE

This study was designed to investigate (1) the contour of the distal tibial cutting surface, and (2) the bone mineral density (BMD) of the distal tibial cutting surface used during total ankle arthroplasty (TAA).

METHODS

Eight-four distal tibial models were created using foot and ankle computerized tomographic (CT) images taken from normal people. The distal tibial cutting surface for TAA was determined to be 10 mm proximal to the tibial plafond. The bony contour and BMD values were determined from the CT image at that level. A bounding box was made on the contour and the width and length of the contour was measured. Regional BMD was evaluated by Hounsfield units (HU) value measurement, with 7 regions of interest (ROI) on 8 different directions for all the 84 CT images. Two different observers made independent measurements and mean HU values for all the 56 ROIs were calculated.

RESULTS

Great variations were found among the contours of the cutting surface especially in term of the shape of the anterior and posterior tibial tubercle, and the fibular notch. These variations could be grouped into six categories. For the BMD of the cutting surface, the medial border of the cutting surface did not included cortical bone. The HU value of seven ROIs, which included cortical bone, were significantly greater than all the other ROIs. Few statistical differences were found by multiple comparisons among HU value of all the 49 ROIs without cortex.

CONCLUSIONS

Great variability existed in the shape and the BMD of the distal tibial cutting surface.

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.

Outcome Reporting in Total Ankle Arthroplasty: A Systematic Review

Total ankle arthroplasty is an increasingly utilized treatment for ankle arthritis due to decreasing failure rates and improved outcomes. However, the literature on this procedure remains heterogeneous with large variability in outcome reporting methods. PRISMA guidelines were used to systematically review outcome reporting measures used in prospective studies and randomized control trials on total ankle arthroplasty published in 15 high-impact journals between Jan 1, 2009-May 1, 2020. A total of 43 studies were included and outcome measures were grouped into seven categories: pain, subjective function, patient satisfaction, complications, objective function, implant survivorship, and imaging. The most common topic of study was implant design followed by differences in outcomes when comparing total ankle arthroplasty and arthrodesis. The most commonly reported outcome measure was post-surgical complications. No study reported on all seven categories, while 22 (51.2%) studies reported on four or more. Subjective measures had significant variability with fifteen different Patient Reported Outcome Measures used across the studies. While the included studies were quite comprehensive, there was little consistency in reporting outcomes after total ankle arthroplasty. With improving outcomes and techniques in total ankle arthroplasty, and thus an expected increase in utilization and number of published studies, efforts should be made to use commonly employed outcome reporting methods to facilitate comparison of results across studies.

Intermediate-Term Outcomes of a Third-Generation, 2-Component Total Ankle Prosthesis

BACKGROUND

Short-term outcomes for the INBONE I and INBONE II tibial stems have been favorable. The INBONE-II talus has been shown to have lower reoperation and failure rates compared to its predecessor at short term follow-up. The purpose of the present study was to assess mid-term outcomes for the third generation, two component total ankle prosthesis at 5 to 9 years follow-up, evaluating both the tibial and talar components.

METHODS

All patients who underwent primary total ankle arthroplasty (TAA) with INBONE-II between July 2010 and July 2014 at a single institution and who were at least 5 years postoperative were included. A total of 15 ankles with a mean follow-up of 85 months (range, 61-113 months) met the criteria. Radiographs were assessed using coronal and sagittal alignment parameters preoperatively, at 6 weeks postoperatively, and at the most recent follow-up. Medical records were reviewed and revisions, reoperations, and complications were classified according to the criteria established by Vander Griend et al and Glazebrook et al, respectively.

RESULTS

The survivorship of the prosthesis at a mean of 85 months was 93.7%. The coronal and sagittal tibiotalar alignments 6 weeks after surgery were 2.1 degrees (P = .081) and 36% (P = .15), respectively. Maintenance of this alignment was observed during the latest follow-up (P = .684 and P = .837, respectively). One ankle (6.7%) required early component revision, while 4 (26.7%) required a non-implant-related revision. Six complications (2 high grade, 1 intermediate, and 3 low) in 5 ankles (33.3%) were recorded according to the Glazebrook classification system.

CONCLUSION

The present study is the first to report midterm follow-up after TAA with this third-generation, 2-component prothesis. High survivorship, maintenance of correction, and a low incidence of major complications were observed in this small case series. The most common complication overall was lateral gutter impingement, which accounted for the majority of the nonrevisional reoperations.

LEVEL OF EVIDENCE

Level IV, case series.

Outcomes of Ankle Arthrodesis Conversion to Total Ankle Arthroplasty: A Systematic Review

Ankle arthrodesis (AA) provides reliable pain relief, good patient satisfaction scores, and improved overall function. However, this procedure has been associated with numerous complications and sequelae, such as pseudoarthrosis, malunion, gait abnormalities, increased demand on surrounding joints, and a long period of convalescence. Conversion to total ankle arthroplasty (TAA) is a potential option in the management of these complex and challenging situations. The purpose of this study is to investigate the outcomes of AA conversion to TAA. A systematic review of electronic databases was performed. Six studies involving 172 ankles met inclusion criteria. The weighted mean preoperative Visual Analogue Scale (VAS) score at the time of TAA conversion was 7.8 and the weighted mean postoperative VAS score at the time of final follow-up was 2.5. The weighted mean preoperative AOFAS score at the time of TAA conversion was 32 and the weighted mean postoperative AOFAS score at the time of final follow-up was 72.4. The rate of salvage tibiotalocalcaneal arthrodesis was 2.3% and rate of transtibial amputation was also 2.3% after attempted conversion from initial AA to TAA. Conversion of AA to TAA appears to be a viable option to improve patient outcomes and prevent extensive hindfoot arthrodesis and transtibial amputation. More prospective studies with consistent reporting of outcomes, complications, and revision rates with long-term follow-up are needed.

Total Ankle Arthroplasty Survivorship: A Meta-analysis

The gold standard for management of end-stage ankle arthritis was previously ankle arthrodesis; however, improvements in total ankle replacements are making this a more viable treatment option. The primary aim of this meta-analysis was to evaluate the survivorship of total ankle replacement implants currently in use. An extensive search strategy initially captured 20,842 citations that were evaluated for relevance. Abstract screening produced 97 articles to be read in entirety, of which 10 articles studying 1963 implants met all prospective inclusion criteria for analysis. Overall survivorship of all implants was 93.0% (95% confidence interval, 85.2-96.9) using a random effect model. There was significant heterogeneity between the studies (Q = 131.504). Meta-regression identified an inverse relationship between survivorship and study follow-up duration (p < .0001). Furthermore, age (p = .36) and implant type (fixed-bearing [95.6%, 95% confidence interval, 85.9-98.7] versus mobile-bearing ]89.4%, 95% confidence interval, 79.6%-94.8%]) did not have a statistically significant impact on survivorship, p = .213. However, patients with higher preoperative functional scores had improved survivorship (p = .001). Complications were inconsistently reported with varied definitions. In order of reported frequency, complications were classified into technical error (28.15%), subsidence (16.89%), implant failure (13.28%), aseptic loosening (6.3%), intraoperative fracture (5.67%), wound problems (4.3%), deep infection (1%), and postoperative fracture (0.0001%). Overall study quality was low, with only 10% being prospective and 90% from nonregistry data. The results from this meta-analysis revealed a promising overall survivorship of current implants in use for total ankle replacement; however higher quality studies with standardized outcomes measures are needed.

Bone Mineral Density Testing in Patients Undergoing Total Ankle Arthroplasty: Should We Pay More Attention to the Bone Quality?

Total ankle arthroplasty (TAA) has become one of the standard treatments for end-stage ankle arthritis. Long-term TAA survivorship is reported from 63% to 95%, with aseptic loosening being the most common mode of failure. Several studies have shown that low bone mineral density (BMD) of the hip affects the longevity of prosthetic implants. The role of Dual energy X-ray absorptiometry for TAA has not been established. The purpose of this review was to define the role of BMD in TAA outcomes and the role of Dual energy X-ray absorptiometry in measuring periprosthetic BMD. There is a paucity of information and published literature regarding the relationship between BMD and TAA. From attempting this systematic review, we hope to highlight that much of the focus in total ankle arthroplasty has emphasized implants and relatively little has focused on the quality of bone into which the prostheses are implanted.

Effect of Gender Differences on Patient-Reported Outcomes and Complications in Total Ankle Replacement

BACKGROUND

The purpose of this study was to evaluate gender differences in patient outcomes and complications following total ankle replacement (TAR).

METHODS

Consecutive patients who underwent primary TAR from July 2007 through May 2016 were prospectively followed and retrospectively reviewed. Demographic, operative, patient-reported outcomes (PROs), and complication data were collected and analyzed. PROs included the visual analog scale (VAS), 36-Item Short-Form Health Survey (SF-36), American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scale, and Short Musculoskeletal Function Assessment (SMFA). A total of 475 patients were evaluated, including 248 males (52.2%) and 227 females (47.8%) with an average of 56.8 months follow-up.

RESULTS

Women were more likely to have inflammatory arthritis (13.7% vs 2.8%; P < .01) and significantly worse preoperative SF-36 total, SF-36 mental health component, AOFAS total, AOFAS pain, SMFA function, and SMFA bother scores (all P < .05). Both genders demonstrated significant improvement in PROs at 1, 2, and 5 years. The magnitude of improvement was similar between genders for all PROs (all P < .05) with the exception of SF-36 physical function, which was greater in men. Females underwent more nonrevision reoperations (32.2% vs 22.6%; P = .0191), but there was no significant difference in failure rates (male 7.3% vs female 3.5%; P = .07). The reoperation and failure rates at 2 years postoperation were 10.1% and 1.6% for men and 18.5% and 0.9% for women, respectively.

CONCLUSION

Women undergoing TAR were more likely to have worse preoperative PROs and higher rates of nonrevision reoperations, which remains true when controlling for their increased incidence of inflammatory arthritis. However, women reported similar improvements in PROs and had similar prosthetic survival rates as men. Increased understanding of these disparities, combined with gender-based interventions, may further advance patient outcomes.

LEVEL OF EVIDENCE

Level III, therapeutic, retrospective comparative series.

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.

Long-term Functional Results of Total Ankle Arthroplasty in Stiff Ankles

BACKGROUND

Total ankle arthroplasty (TAA) is advocated over ankle arthrodesis to preserve ankle motion (ROM). Clinical and gait analysis studies have shown significant improvement after TAA. The role and outcomes of TAA in stiff ankles, which have little motion to be preserved, has been the subject of limited investigation. This investigation evaluated the mid- to long-term functional outcomes of TAA in stiff ankles.

METHODS

A retrospective study of prospectively collected functional gait data in 33 TAA patients at a mean of 7.6 (5-13) years postoperatively used 1-way analysis of variance and multivariate regression analysis to compare among preoperative and postoperative demographic data (age, gender, body mass index, years postsurgery, and diagnosis) and gait parameters according to quartiles of preoperative sagittal ROM.

RESULTS

The stiffest ankles had a mean ROM of 7.8 degrees, compared to 14.3 degrees for the middle 2 quartiles, and 21.0 degrees for the most flexible ankles. Patients in the lowest quartile (Q1) also had statistically significantly lower step length, speed, max plantarflexion, and power preoperatively. Postoperatively, they increased step length, speed, max plantarflexion, and ankle power to levels comparable to patients with more flexible ankles preoperatively (Q2, Q3, and Q4). They had the greatest absolute and relative increases in these parameters of any group, but the final total ROM was still statistically significantly the lowest.

CONCLUSION

Preoperative ROM was predictive of overall postoperative gait function at an average of 7.6 (range 5-13) years. Although greater preoperative sagittal ROM predicted greater postoperative ROM, the stiffest ankles showed the greatest percentage increase in ROM. Patients with the stiffest ankles had the greatest absolute and relative improvements in objective function after TAA, as measured by multiple gait parameters. At intermediate- to long-term follow-up, patients with stiff ankles maintained significant functional improvements after TAA.

LEVEL OF EVIDENCE

Level III, comparative study.

Anterior placement of the talar component in total ankle arthroplasty: A risk factor for talar component subsidence

BACKGROUND

Component subsidence is considered as a cause of revision surgery. The talar component subsidence may be a risk factor for revision surgery; however, there are no reports regarding talar component placement and subsidence amount following total ankle arthroplasty (TAA). We therefore investigated the relationship between talar component placement and subsidence amount.

METHODS

Fifty-two ankles from 49 patients (age: 71 years [range 62-83], 13 male/ 36 female), who underwent TAA with mean follow-up of 36 months (range 12-83), were included. The subjects were divided into two groups based on talar component placement: anterior placement (n = 20, group A) and posterior placement (n = 32, group P) using weight-bearing lateral plain radiographs. The amount of the talar component subsidence and clinical outcomes, which included the Japanese Society for Surgery of the Foot (JSSF) scale, range of the motion (ROM) and the revision rate, were compared between the groups.

RESULTS

Talar component subsidence was significantly higher in group A (2.1 ± 2.0 mm) than in group P (0.6 ± 1.4 mm, P = .017). There was no significant difference in the JSSF scale and ROM between group A and group P. The revision rate was 10.0% in group A and 6.3% in group P, albeit not statistically significant.

CONCLUSION

Greater talar component subsidence was observed when the talar component was placed more anteriorly, suggesting that anterior placement of the talar component may need to be avoided during the surgery in order to minimize the postoperative talar component subsidence.

Functional Outcomes of Total Ankle Arthroplasty at a Mean Follow-up of 7.6 Years: A Prospective, 3-Dimensional Gait Analysis

BACKGROUND

In vivo gait analysis provides objective measurement of patient function and can quantify that function before and after ankle reconstruction. Previous gait studies have shown functional improvement for up to 4 years following total ankle arthroplasty (TAA), but to date, there are no published studies assessing function at ≥5 years following TAA. We hypothesized that patients who underwent TAA would show significant improvements in walking function at a minimum follow-up of 5 years, compared with their preoperative function, as measured by changes in temporospatial, kinematic, and kinetic gait parameters.

METHODS

Three-dimensional gait analysis with a 12-camera digital motion-capture system and double force plates was utilized to record temporospatial, kinematic, and kinetic measures in 33 patients who underwent TAA with either the Scandinavian Total Ankle Replacement (Stryker; n = 28) or Salto Talaris Ankle (Integra LifeSciences; n = 5). Gait analysis was performed preoperatively and at a minimum follow-up of 5 years (mean, 7.6 years; range, 5 to 13 years).

RESULTS

Significant improvements were observed in multiple gait parameters, with temporospatial increases in cadence (+9.5 steps/min; p < 0.0001), step length (+4.4 cm; p = 0.0013), and walking speed (+0.2 m/s; p < 0.0001), and kinematic increases in total sagittal range of motion (+2.0°; p = 0.0263), plantar flexion at initial contact (+2.7°; p = 0.0044), and maximum plantar flexion (+2.0°; p = 0.0488). Kinetic analysis revealed no loss of peak ankle power, despite patients aging.

CONCLUSIONS

To our knowledge, this is the first study to report 7-year functional outcomes of TAA, quantified by objective, in vivo measurements of patient gait. Patients were shown to have sustained improvement in multiple objective parameters of gait compared with preoperative function.

LEVEL OF EVIDENCE

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

Adverse events related to total ankle replacement devices: an analysis of reports to the United States Food and Drug Administration

Background

The published outcomes of total ankle replacement (TAR) implants came from limited institutions creating observational bias. For broader perspective, we queried the Food and Drug Administration’s (FDA) Manufacturer and User Facility Device Experience (MAUDE) voluntary database to explore complications reported outside published literature.

Methods

The database was reviewed retrospectively between November 2011 and April 2019 using two product codes assigned to six TAR devices.

Results

Among 648 relevant reports available in the database, common complications were aseptic loosening (19.3%), infection (18.2%), and alignment/mechanical issues (16.5%). Others included instrument/instrumentation complications, impingement, polyethylene problems, fractures, avascular necrosis of talus (AVN), and packaging issues.

Conclusion

MAUDE database revealed various patterns of device-related malfunctions that have been under-reported in published data. Despite inconsistency in the available reports, it provided opportunities for improvements in quality control, device design, and ultimately patient safety. Database would be further strengthened by more robust reporting mechanism or mandatory reporting of device-related complications.

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.

Radiographic and Clinical Outcomes of the Salto Talaris Total Ankle Arthroplasty

BACKGROUND

The Salto Talaris is a fixed-bearing implant first approved in the US in 2006. While early surgical outcomes have been promising, mid- to long-term survivorship data are limited. The aim of this study was to present the survivorship and causes of failure of the Salto Talaris implant, with functional and radiographic outcomes.

METHODS

Eighty-seven prospectively followed patients who underwent total ankle arthroplasty with the Salto Talaris between 2007 and 2015 at our institution were retrospectively identified. Of these, 82 patients (85 ankles) had a minimum follow-up of 5 (mean, 7.1; range, 5-12) years. The mean age was 63.5 (range, 42-82) years and the mean body mass index was 28.1 (range, 17.9-41.2) kg/m². Survivorship was determined by incidence of revision, defined as removal/exchange of a metal component. Preoperative, immediate, and minimum 5-year postoperative AP and lateral weightbearing radiographs were reviewed; tibiotalar alignment (TTA) and the medial distal tibial angle (MDTA) were measured to assess coronal talar and tibial alignment, respectively. The sagittal tibial angle (STA) was measured; the talar inclination angle (TIA) was measured to evaluate for radiographic subsidence of the implant, defined as a change in TIA of 5 degrees or more from the immediately to the latest postoperative lateral radiograph. The locations of periprosthetic cysts were documented. Preoperative and minimum 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscales were compared.

RESULTS

Survivorship was 97.6% with 2 revisions. One patient underwent tibial and talar component revision for varus malalignment of the ankle; another underwent talar component revision for aseptic loosening and subsidence. The rate of other reoperations was 21.2% (n = 18), with the main reoperation being exostectomy with debridement for ankle impingement (n = 12). At final follow-up, the average TTA improved 4.4 (± 3.8) degrees, the average MDTA improved 3.4 (± 2.6) degrees, and the average STA improved 5.3 (± 4.5) degrees. Periprosthetic cysts were observed in 18 patients, and there was no radiographic subsidence. All FAOS subscales demonstrated significant improvement at final follow-up.

CONCLUSIONS

We found the Salto Talaris implant to be durable, consistent with previous studies of shorter follow-up lengths. We observed significant improvement in radiographic alignment as well as patient-reported clinical outcomes at a minimum 5-year follow-up.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

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

AIMS

Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°.

METHODS

A matched cohort of patients similar for demographics and components used but differing in preoperative coronal-plane tibiotalar valgus deformity ≥ 15° (valgus, n = 50; 52% male, mean age 65.8 years (SD 10.3), mean body mass index (BMI) 29.4 (SD 5.2)) or < 15° (control, n = 50; 58% male, mean age 65.6 years (SD 9.8), mean BMI 28.7 (SD 4.2)), underwent TAA by one surgeon. Preoperative and postoperative radiographs, Ankle Osteoarthritis Scale (AOS) pain and disability and 36-item Short Form Health Survey (SF-36) version 2 scores were collected prospectively. Ancillary procedures, secondary procedures, and complications were recorded.

RESULTS

At mean 5.1 years follow-up (SD 2.6) (valgus) and 6.6 years (SD 3.3) (controls), mean AOS scores decreased and SF-36 scores increased significantly in both groups. Improvements in scores were similar for both groups - AOS pain: valgus, mean 26.2 points (SD 24.2), controls, mean 22.3 points (SD 26.4); AOS disability: valgus, mean 41.2 points (SD 25.6); controls, mean 34.6 points (SD 24.3); and SF-36 PCS: valgus, mean 9.1 points (SD 14.1), controls, mean 7.4 points (SD 9.8). Valgus ankles underwent more ancillary procedures during TAA (40 (80%) vs 13 (26%)) and more secondary procedures postoperatively (18 (36%) vs 7 (14%)) than controls. Tibiotalar deformity improved significantly (p < 0.001) towards a normal weightbearing axis in valgus ankles. Three valgus and four control ankles required subsequent fusion, including two for deep infections (one in each group).

CONCLUSION

Satisfactory mid-term results were achieved in patients with preoperative valgus malalignment ≥ 15°, but they required more adjunctive procedures during and after TAA. Valgus coronal-plane deformity ≥ 15° is not an absolute contraindication for TAA if associated deformities are addressed. Cite this article: Bone Joint J 2020;102-B(12):1689-1696.

Outcome after total ankle arthroplasty with a minimum of five years follow-up: A systematic review and meta-analysis

BACKGROUND

Total ankle arthroplasty (TAA) is increasingly gaining recognition as an alternative to ankle arthrodesis in the treatment of end-stage ankle arthritis. Despite high rates of adverse events during early inception, newer generations of uncemented prosthesis and design modifications have improved outcomes. Questions remain regarding the long-term outcomes and implant survivorship of TAA.

AIM

This analysis aims to establish an updated review of intermediate and long-term clinical outcome and complication profile of TAA.

PATIENTS AND METHODS

A multi database search was performed on 14th October 2018 according to PRISMA guidelines. All articles that involved patients undergoing uncemented TAA with 5 years minimum follow-up, reported clinical outcome or complication profile of TAA were included. Seventeen observational studies were included in the review, with 1127 and 262 ankles in the 5 and 10 years minimum follow-up groups respectively.

RESULTS

Mean difference between pre- and post-operative AOFAS score was 43.60 (95%CI: 37.51-49.69, p<0.001) at 5 years minimum follow-up. At 5 years minimum follow-up, pooled proportion (PP) of prostheses revision for any reason other than polyethylene exchange was 0.122 (95%CI: 0.084-0.173), all cause revision was 0.185 (95%CI: 0.131-0.256), unplanned reoperation was 0.288 (95%CI: 0.204-0.390) and all infection was 0.033 (95%CI: 0.021-0.051). At 10 years minimum follow-up, PP of prostheses revision for any reason other than polyethylene exchange was 0.202 (95%CI: 0.118-0.325), all cause revision was 0.305 (95%CI: 0.191-0.448), unplanned reoperation was 0.422 (95%CI: 0.260-0.603) and all infection was 0.029 (95%CI: 0.013-0.066).

CONCLUSION

Despite good intermediate and long-term functional outcome measures, TAA has relatively higher revision surgery prevalence with longer follow-up periods. Further research should be directed towards identifying patient populations that would best benefit from TAA and those at greatest risk of requiring revision surgery.

Salvage Arthrodesis for Failed Total Ankle Replacement

Salvage arthrodesis for failed total ankle replacement can be a successful procedure. The decision to perform salvage arthrodesis is based on many factors, but the following are the most important indications: severe loss of bonestock (tibia, talus, or both), inadequate soft tissue coverage, or the inability to eradicate an infection. With few revision implants on the market, salvage arthrodesis is currently the most common treatment for failed replacement and justification for revision ankle replacement is limited when any of these factors are present.

Positive and negative factors for the treatment outcomes following total ankle arthroplasty? A systematic review

BACKGROUND

Patient selection, surgeon's experience and implant design play an integral role and affect the treatment outcomes of total ankle arthroplasty (TAA). The aims of this study were to investigate the positive and negative attributes that correlate with different clinical and radiographic outcomes.

METHODS

Eight-nine studies matched the inclusion criteria: (1) studies of primary TAA with uncemented prosthesis; (2) mean follow-up of no less than 2-year; (3) reports of clinical and radiographic outcomes, and exclusion criteria: (1) non-English study; (2) more than one type of prosthesis without separated data; (3) kin studies with shorter follow-up or smaller cohort. Age, etiology, preoperative deformity, surgeon's experience, follow-up duration and prosthetic type were studied with respect to different outcomes by mixed-effects logistic regression analysis.

RESULTS

Patients factor: older patients reported less pain or stiffness and demonstrated less radiographic loosening which did not require additional surgical intervention. More traumatic arthritis experienced adjacent joints degeneration after TAA. Surgeon factor: less experienced surgeons had more intraoperative complications. Lack of experience for complications management without implant retrieval during early period might result in more revisions or fusion was done. Prosthetic factor: updated instrumentation decreased malalignment. If the polyethylene (PE) insert was significantly narrower than the metal components more implant instability and subsequent severe particulate wear was seen. Designs with flat-on-flat articulation and ridge at the center of the talar component associated with more PE fracture. Minimal bone resection reduced postoperative fractures. A flat cut of the tibial component and a flat undersurface with press-fit by two screws or pegs of the talar component demonstrated less postoperative fractures, whereas a syndesmosis fusion and a small triangular shape with one central fin of the talar component experienced more loosening which did not require additional surgery. Anatomic conical shape of the talar component seemed to reduce adjacent joint degeneration. Finally, fewer failures were found in patients who received HINTEGRA and Salto Talaris.

CONCLUSIONS

Based on our investigation, some positive and negative factors for different clinical and radiographic outcomes were found, which should be taken into consideration in clinical practice and ankle implant design.

Comparison of Tibial and Talar Bone Density in Patients Undergoing Total Ankle Replacement vs Non-Ankle Arthritis Matched Controls

BACKGROUND

Bone quality in the distal tibia and talus is an important factor contributing to initial component stability in total ankle replacement (TAR). However, the effect of ankle arthritis on bone density in the tibia and talus remains unclear. The objective of this study was to compare bone density of tibia and talus in arthritic and nonarthritic ankles as a function of distance from ankle joint.

METHODS

We retrospectively reviewed 93 end-stage ankle arthritis patients who had preoperative nonweightbearing ankle computed tomography (CT) and identified a cohort of 83 nonarthritic ankle patients as a demographic-matched control group. A region of interest tool was used to calculate Hounsfield unit (HU) values in the cancellous region of the tibia and talus. Measurements were obtained on axial cut CTs from 6 to 12 mm above the tibial plafond, and 1 to 4 mm below the talar dome. HU measurements between groups and the decrease of HU at the relative level in each group were compared.

RESULTS

Arthritic ankles demonstrated significantly greater mean bone density than nonarthritic ankles at between 6 and 10 mm above the joint in the tibia (P < .05). No significant difference in bone density between 10 and 12 mm from the joint in the tibia nor at any level of the talus was found between groups. In both groups, bone density decreased significantly at each successive level away from the ankle joint.

CONCLUSION

Ankle arthritis patients demonstrated greater or equal bone density in both the tibia and talus compared to demographic-matched controls. In both groups, bone density decreased with increasing distance away from the articular surface. In TAR, tibial bone resection between 6 and 8 mm may provide improved initial implant stability.

LEVEL OF EVIDENCE

Level III, comparative study.

Prospective Randomized Trial Comparing Mobile-Bearing and Fixed-Bearing Total Ankle Replacement

BACKGROUND

Outcomes of total ankle replacement for the treatment of end-stage ankle arthritis continue to improve. Debate continues whether a mobile-bearing total ankle replacement (MB-TAR) or a fixed-bearing total ankle replacement (FB-TAR) is superior, with successful outcomes reported long term for MB-TAR and at intermediate- to long-term follow-up for newer generation FB-TAR. Although comparisons between the 2 total ankle designs have been reported, to our knowledge, no investigation has compared the 2 designs with a high level of evidence. This prospective, randomized controlled trial conducted at a single institution compares patient satisfaction, functional outcomes, and radiographic results of the mobile-bearing STAR and the fixed-bearing Salto-Talaris in the treatment of end-stage ankle arthritis.

METHODS

Between November 2011 and November 2014, adult patients with end-stage ankle osteoarthritis failing nonoperative treatment were introduced to the study. With informed consent, 100 patients (31 male and 69 female, average age 65 years, range 35-85 years) were enrolled; a demographic comparison between the 2 cohorts was similar. Exclusion criteria included inflammatory arthropathy, neuropathy, weight exceeding 250 pounds, radiographic coronal plane deformity greater than 15 degrees, or extensive talar dome wear pattern ("flat-top talus"). Prospective patient-reported outcomes, physical examination, and standardized weightbearing ankle radiographs were obtained preoperatively, at 6 and 12 months postoperatively, and then at yearly intervals. Data collection included visual analog pain score, Short Form 36, Foot and Ankle Disability Index, Short Musculoskeletal Functional Assessment, and American Orthopaedic Foot & Ankle Society ankle-hindfoot score. Surgeries were performed by a nondesign team of orthopedic foot and ankle specialists with total ankle replacement expertise. Statistical analysis was performed by a qualified statistician. At average follow-up of 4.5 years (range, 2-6 years) complete clinical data and radiographs were available for 84 patients; 7 had incomplete data, 1 had died, 4 were withdrawn after enrolling but prior to surgery, and 4 were lost to follow-up.

RESULTS

In all outcome measures, the entire cohort demonstrated statistically significant improvements from preoperative evaluation to most recent follow-up with no statistically significant difference between the 2 groups. Radiographically, tibial lucency/cyst formation was 26.8% and 20.9% for MB-TAR and FB-TAR, respectively. Tibial settling/subsidence occurred in 7.3% of MB-TAR. Talar lucency/cyst formation occurred in 24.3% and 2.0% of MB-TAR and FB-TAR, respectively. Talar subsidence was observed in 21.9% and 2.0% of MB-TAR and FH-TAR, respectively. Reoperations were performed in 8 MB-TARs and 3 FH-TARs, with the majority of procedures being to relieve impingement or treat cysts and not to revise or remove metal implants.

CONCLUSION

With a high level of evidence, our study found that patient-reported and clinical outcomes were favorable for both designs and that there was no significant difference in clinical improvement between the 2 implants. The incidence of lucency/cyst formation was similar for MB-TAR and FH-TAR for the tibial component, but the MB-TAR had greater talar lucency/cyst formation and tibial and talar subsidence. As has been suggested in previous studies, clinical outcomes do not necessarily correlate with radiographic findings. Reoperations were more common for MB-TAR and, in most cases, were to relieve impingement or treat cysts rather than revise or remove metal implants.

LEVEL OF EVIDENCE

Level I, prospective randomized study.

Mid-Term Prospective Clinical and Radiographic Outcomes of a Modern Fixed-Bearing Total Ankle Arthroplasty

The early outcomes of the Salto Talaris® Total Ankle Prosthesis have been promising, but information on its mid-term outcomes is still sparse. The purpose of this study was to evaluate the mid-term clinical and radiographic outcomes of this implant among a prospective cohort of patients who underwent total ankle replacement for various etiologies. Forty-six patients (50 ankles) were consecutively enrolled in the study. Our primary aim was to assess implant survivorship as determined by the removal or revision of the implant metal components or conversion to arthrodesis. Our secondary aim was to gauge patient outcomes by using commonly used outcome scores and assess ankle range of motion using goniometric and radiographic methods. We report 100% survivorship of the implant at a mean follow-up of 4.9 years. Compared with preoperative levels, all clinical outcome scores showed significant improvement at the 1-year, 2-year, and 5-year and longer follow-up. The mean clinical ROM improved from 27.7° ± 10.7° preoperatively to 40.0° ± 12.3° at the 2-year follow-up (p < .001). The mean radiographic ROM improved from 23.0° ± 10.2° preoperatively to 27.2° ± 9.1° at the 2-year follow-up (p = .007). Reoperations or secondary procedures were performed on 6 (12%) ankles, with the most common procedure being gutter debridement for impingement symptoms. The study confirms that the excellent survivorship seen with the implant in the early studies extends to mid-term follow-up as well. Patients could expect to see improvement in pain relief and activity well into 5 years after surgery and retain sufficient ankle range of motion for normal gait.

Total Ankle Replacement Options

Total ankle arthroplasty has been in development for more than 40 years. Although early designs were experimental with high failure rates, current implants are significantly improved, showing promising functional results and clinical outcomes. Total ankle replacement designs are split into mobile-bearing and fixed-bearing designs. When deciding whether to perform ankle arthroplasty, many factors need to be considered to determine if the patient is suitable and which implant is the best fit for patient and surgeon. Many prostheses are available in the United States today and the purpose of this article is to outline options for foot and ankle surgeons.

Outcomes Following Total Ankle Arthroplasty: A Review of the Registry Data and Current Literature

End-stage ankle arthritis has a significant effect on function and quality of life. Total ankle arthroplasty continues to emerge as a safe and effective treatment of ankle arthritis. Ankle arthroplasty preserves motion at the ankle joint, while still achieving the primary goal of pain relief. With encouraging outcomes and improved implant longevity, there has been significant improvement on the results of first-generation implants. Further high-quality studies are required to clarify outcomes post ankle arthroplasty. This article reviews the latest data from national registries and the wider literature to evaluate the current status with outcomes of modern total ankle replacements.

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.