Current concepts review: total ankle arthroplasty

Outcomes of Total Ankle Replacement Versus Ankle Arthrodesis for the Treatment of End-Stage Ankle Arthritis: A Concise Follow-up, at a Minimum of 10 Years, of a Previous Report

ABSTRACT

Despite the increasing utilization of total ankle replacement (TAR) for end-stage ankle arthritis, there remains a paucity of long-term follow-up data comparing arthroplasty to arthrodesis. The aim of the current paper was to provide the long-term clinical outcomes of TAR and ankle arthrodesis (AA), measured with use of validated scoring instruments, in a prospective multicenter cohort of patients with ankle arthritis. This cohort from the Canadian Orthopaedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstruction Database comprised patients who underwent TAR or AA between 2001 and 2007. Data collection included demographics, comorbidities, and Ankle Osteoarthritis Scale and Short Form-36 scores. A total of 211 patients were included in the present study, with a minimum follow-up of 10 years (range, 10 to 18 years) and a mean follow-up of 13.2 years. In this cohort, the baseline characteristics of those who underwent AA and those who underwent TAR differed with respect to mean age (53.8 versus 61.3 years; p < 0.001), smoking status (31% versus 50% with no smoking history; p < 0.001), and inflammatory arthritis diagnosis (2% versus 17%; p = 0.005). Patients in the AA group had a greater chance of having no further surgery following their index procedure compared with those in the TAR group (70% versus 58%; p = 0.02). The TAR and AA groups demonstrated similar functional outcomes. In conclusion, the long-term clinical outcomes of TAR and AA were similar in a diverse cohort in which the treatment was tailored to the condition of the patient.

LEVEL OF EVIDENCE

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

Challenges in Total Ankle Replacement in Post-Traumatic Ankle Osteoarthritis

A previous trauma is the most common origin of ankle osteoarthritis. Patients with post-traumatic osteoarthritis are generally younger. Due to the previous trauma and surgical treatment, the surrounding soft tissues are often scarred and inelastic. Structural changes of the osteoarthritic ankle are often significant, including deformity and instability, thus making the replacement surgery highly complex. Careful clinical examination and thorough radiographic assessment are mandatory to anticipate potential problems during TAR surgery and complications.

Is the treatment of ankle osteoarthritis changing over time in Italy? Analysis of temporal trends for fusion and arthroplasty in a population-based study from 2001 to 2022 on the National Hospital Discharge Record database

BACKGROUND

Treatment of ankle osteoarthritis by total ankle replacement (TAR) is increasing worldwide. The aim of the study was to present the overall temporal trends of TAR throughout 22 years (2001-2022) in Italy, analyzing the distributions of hospitals by volume of activity and patients by age and sex, drawing on the National Hospital Discharge Record database. Furthermore, as a secondary aim, we compared these trends with those of ankle fusions.

MATERIALS AND METHODS

International Classification of Diseases, 9th Revision, Clinical Modification (ICD9-CM) codes of interest were identified to browse the Italian National Hospital Discharge Record database. Surgical volumes, trends over time, classes of hospital activity volume, sex and age of patients, and population incidence rates were described. The statistical significance of time series trends was assessed by the Cox-Stuart test with randomness as a null hypothesis.

RESULTS

20,248 ankle procedures (total ankle replacements 8853 and ankle fusions 11,395) were extracted from 231,601,523 admissions registered nationally from 2001 to 2022. The yearly total number of TARs significantly increased almost tenfold from 96 to 996 (p < 0.05), while the number of fusions exhibited a stationary behavior (p > 0.05). The increased trend in TAR procedures was concentrated mostly in the North of Italy, with predominantly males between 55 and 64 years of age. The analysis of the number of procedures performed on inhabitants by region and that performed by all the hospitals in the region showed a different pattern across Italy.

CONCLUSIONS

The substantial increase in TARs may be owing to improved implant designs and innovative surgical technologies, which allow the treatment of more severe cases and deformities, previously untreated or treated by a fusion. This trend highlights the need to invest in implementing high quality registries by promoting surgeons' participation in data collection.

LEVEL OF EVIDENCE

population based study, level 1 evidence.

Magnetic Resonance Imaging of Total Ankle Arthroplasty: State-of-The-Art Assessment of Implant-Related Pain and Dysfunction

Total ankle arthroplasty (TAA) is an effective alternative for treating patients with end-stage ankle degeneration, improving mobility, and providing pain relief. Implant survivorship is constantly improving; however, complications occur. Many causes of pain and dysfunction after total ankle arthroplasty can be diagnosed accurately with clinical examination, laboratory, radiography, and computer tomography. However, when there are no or inconclusive imaging findings, magnetic resonance imaging (MRI) is highly accurate in identifying and characterizing bone resorption, osteolysis, infection, osseous stress reactions, nondisplaced fractures, polyethylene damage, nerve injuries and neuropathies, as well as tendon and ligament tears. Multiple vendors offer effective, clinically available MRI techniques for metal artifact reduction MRI of total ankle arthroplasty. This article reviews the MRI appearances of common TAA implant systems, clinically available techniques and protocols for metal artifact reduction MRI of TAA implants, and the MRI appearances of a broad spectrum of TAA-related complications.

Cone-Beam Weight-Bearing Computed Tomography of Ankle Arthritis and Total Ankle Arthroplasty

Weight-bearing computed tomography has multiple advantages in evaluating the hindfoot and ankle. It can assess hindfoot and ankle alignment, pathology in ankle arthritis, and complications related to total ankle replacements. It is an essential tool in ankle osteoarthritis diagnostic, preoperative planning, and total ankle replacement outcomes. It allows for better accuracy and reproducibility of alignment and implant size. In addition, it has the potential to more assertively detect complications related to weight bearing.

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.

Different radius of curvature at the talus trochlea from northern Chinese population measured using 3D model

BACKGROUND

To analyze the curvature characteristics of the talus trochlea in people from northern China in different sex and age groups.

METHODS

Computed tomography scanning data of talus from 61 specimens were collected and constructed as a three-dimensional model by Materialise's Interactive Medical Image Control System(MIMICS) software, anteromedial(AM), posteromedial(PM), anterolateral(AL), and posterolateral(PL) edge, anterior edge of medial trochlea, posterior edge of medial trochlea and anterior edge of lateral trochlea were defined according to the anatomical landmarks on trochlear surface. The curvature radii for different areas were measured using the fitting radius and measure module.

RESULTS

There were significant differences among the talus curvatures in the six areas (F = 54.905, P = 0.000), and more trends in the analytical results were as follows: PM > PL > MP > AL > MA > AM. The average PL radius from specimens aged > 38 years old was larger than that from specimens aged < = 38 years (t=-2.303, P = 0.038). The talus curvature of the AM for males was significantly larger than that for females (t = 4.25, P = 0.000), and the curvature of the AL for males was larger than that for females (t = 2.629, P = 0.010). For observers aged < = 38 years, the AM curvature of the right talus in the male group was significantly larger than that in the female group (P < 0.01). In age < = 38years group, the MA curvature of right talus in male was significantly larger than in female group(P < 0.01), fitting radius of talus for male (21.90 ± 1.97 mm) was significantly greater than female of this(19.57 ± 1.26 mm)(t = 6.894, P = 000). The average radius of the talus in the male population was larger than that in the female population.

CONCLUSION

There was no significant relationship between age and talus curvature for males and females. The radius of curvature in the posterior area was significantly larger than that in the anterior area. We recommend that this characteristic of the talus trochlea should be considered when designing the talus component in total ankle replacement (TAR).

Two-Year Survivorship and Patient-Reported Outcomes of a Prospectively Enrolled Cohort of INFINITY Total Ankle Arthroplasties

BACKGROUND

The INFINITY total ankle implant is a widely and successfully used option for total ankle arthroplasty. The purpose of this study is to assess the 2-year survivorship, complication rates, patient-reported outcomes, and radiologic findings of prospectively enrolled patients undergoing a fixed-bearing total ankle arthroplasty (TAA). This study sought to determine if factors such as traditional vs patient-specific instrumentation, preoperative degree of arthritis, deformity, or etiology of arthritis impact surgical or clinical outcomes.

METHODS

A total of 143 prospectively enrolled patients (148 ankles) underwent TAA with a fixed-bearing total ankle implant between 2017 and 2019 at 9 different institutions by 9 different surgeons. A total of 116 completed 2-year follow-up. Patients were stratified by instrumentation used, degree of preoperative deformity, the Canadian Orthopaedic Foot and Ankle Society (COFAS) grading system, and etiology of arthritis. Outcomes used included implant survivorship and adverse events within 2 years of surgery. Additionally, patient-reported outcomes and radiographs were collected at 6-month, 1-year, and 2-year postoperatively. PROMs used included Ankle Osteoarthritis Score (AOS), Patient-Reported Outcomes Measurement Information System (PROMIS) global health score, the Foot and Ankle Outcome Score (FAOS), and patient satisfaction (rated from excellent to poor).

RESULTS

Implant survivorship at 2 years was 97.79%. There were 17 reoperations (11.5%), with 4 of the implants requiring revision (2.7%). Significant improvements in all PROMs were observed among all subgroups at all postoperative time points without significant variation between subgroups. Patients classified as COFAS type 2 arthritis preoperatively demonstrated significantly more improvement in FAOS Total Symptom Score at the 1- and 2-year measurements than COFAS type 3 patients at both time points.

CONCLUSION

Total ankle arthroplasty with a fixed-bearing implant system is a safe and reliable treatment option for patients with end-stage arthritis regardless of degree of deformity or COFAS grading.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Cone-Beam Weight-Bearing Computed Tomography of Ankle Arthritis and Total Ankle Arthroplasty

Weight-bearing computed tomography has multiple advantages in evaluating the hindfoot and ankle. It can assess hindfoot and ankle alignment, pathology in ankle arthritis, and complications related to total ankle replacements. It is an essential tool in ankle osteoarthritis diagnostic, preoperative planning, and total ankle replacement outcomes. It allows for better accuracy and reproducibility of alignment and implant size. In addition, it has the potential to more assertively detect complications related to weight bearing.

A Novel Orthoplastic Reconstruction of Relapsed Clubfoot With Total Ankle Arthroplasty

Congenital clubfoot is addressed in infancy and rarely persists into adulthood. Ankle arthroplasty is an increasingly popular surgical intervention for patients with ankle arthritis since it allows a natural ankle range of motion and completely replaces a degenerative hindfoot. Here, we describe the first successful total ankle arthroplasty (TAA) for a patient with previously treated congenital clubfoot that reverted later in life. To address the patient's poor soft-tissue integument and reduce the likelihood of post-surgical complications, a perioperative latissimus muscle-free flap was performed. This two-staged, novel orthoplastic intervention addressed our patient's ankle issues and appears to be a viable option for clubfoot patients.

Magnetic Resonance Imaging of Total Ankle Arthroplasty: State-of-The-Art Assessment of Implant-Related Pain and Dysfunction

Total ankle arthroplasty (TAA) is an effective alternative for treating patients with end-stage ankle degeneration, improving mobility, and providing pain relief. Implant survivorship is constantly improving; however, complications occur. Many causes of pain and dysfunction after total ankle arthroplasty can be diagnosed accurately with clinical examination, laboratory, radiography, and computer tomography. However, when there are no or inconclusive imaging findings, magnetic resonance imaging (MRI) is highly accurate in identifying and characterizing bone resorption, osteolysis, infection, osseous stress reactions, nondisplaced fractures, polyethylene damage, nerve injuries and neuropathies, as well as tendon and ligament tears. Multiple vendors offer effective, clinically available MRI techniques for metal artifact reduction MRI of total ankle arthroplasty. This article reviews the MRI appearances of common TAA implant systems, clinically available techniques and protocols for metal artifact reduction MRI of TAA implants, and the MRI appearances of a broad spectrum of TAA-related complications.

The Burden of Revision Total Ankle Replacement Has Increased From 2010 to 2020

Background

Total ankle replacement (TAR) surgery has increased in recent decades. The aim of this study was to investigate the evolving burden of revision surgery and risk factors and timing of revision or explant.

Methods

Using the 2010 to 2020 PearlDiver M151Ortho data set, this retrospective cohort study identified primary TAR, TAR revision, and TAR explant patients via Current Procedural Terminology (CPT) and International Classification of Disease Procedural (ICD-P) codes. This database contains billing claims information across all payers and sites of care in the United States. Patient factors investigated included age, sex, and Elixhauser Comorbidity Index (ECI). Annual incidence for primary TAR was normalized per 100 000 covered lives in the data set for each year of study and recorded. Annual incidence of revision TAR and explant were normalized per 100 TARs performed for each year of study. Multivariate logistic regression analyses were performed to determine independent risk factors for revision TAR or explant. For explants, the eventual intervention by 2 years was analyzed. Ten-year timing and survival to revision or explant surgery following unilateral TAR were characterized.

Results

A total of 10 531 primary, 1218 revision, and 1735 explant TARs were identified. After normalization, TAR utilization increased by 284% from 2010 to 2020, annual TAR revisions rose 28%, and annual TAR explants decreased 65%. Independent predictors of revision TAR were younger age (odds ratio [OR] 1.29 per decade decrease) and higher ECI (OR 1.23 per 2-point increase). Independent predictors of explant included younger age (OR 1.80 per decade decrease), female sex (OR 1.17), and higher ECI (OR 1.35 per 2-point increase). The 10-year implant survival rate was 91.8%, of which 73% of revisions and 83% of explants occurred in the first 3 years following index TAR.

Conclusion

TAR utilization has grown substantially over the past decade, with minimal increases in the annual rate of revision surgery with respect to index procedures performed.

Level of Evidence

Level III, retrospective cohort study.

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.

Imaging and Treatment of Posttraumatic Ankle and Hindfoot Osteoarthritis

Posttraumatic osteoarthritis of the ankle and hindfoot is a common and frequently debilitating disorder. 70% to 90% of ankle osteoarthritis is related to prior trauma that encompasses a spectrum of disorders including fractures and ligamentous injuries that either disrupt the articular surface or result in instability of the joint. In addition to clinical evaluation, imaging plays a substantial role in the treatment planning of posttraumatic ankle and hindfoot osteoarthritis. Imaging evaluation must be tailored to specific clinical scenarios and includes weight bearing radiography that utilizes standard and specialty views, computed tomography which can be performed with a standard or a weight bearing technique, magnetic resonance imaging, and ultrasound evaluation. This review article aims to familiarize the reader with treatment rationale, to provide a brief review of surgical techniques and to illustrate expected imaging appearances of common operative procedures performed in the setting of posttraumatic ankle and hindfoot osteoarthritis, such as joint-preserving procedures, ankle fusion, subtalar fusion, tibiotalarcalcaneal fusion and ankle arthroplasty. Preoperative findings will be discussed along with the expected postoperative appearance of various procedures in order to improve detection of their complications on imaging and to provide optimal patient care.

Comparing 4-Year Changes in Patient-Reported Outcomes Following Ankle Arthroplasty and Arthrodesis

BACKGROUND

The rate of total ankle arthroplasty (TAA) is increasing relative to ankle arthrodesis (AA) for patients seeking surgical treatment for end-stage ankle arthritis. Patients and providers would benefit from a more complete understanding of the rate of improvement, the average length of time to achieve maximal function and minimal pain, and whether there is a greater decline in function or an increase in pain over time following TAA compared with AA. The objectives of this study were to compare treatment changes in overall physical and mental function and ankle-specific function, as well as pain intensity at 48 months after TAA or AA in order to determine if the improvements are sustained.

METHODS

This was a multisite prospective cohort study that included 517 participants (414 TAA and 103 AA) who presented for surgical treatment. Participants were compared 48 months after surgery using the Foot and Ankle Ability Measure (FAAM) Activities of Daily Living and Sports subscales (0 to 100 points), the Short Form-36 (SF-36) Physical and Mental Component Summary (PCS and MCS) scores (0 to 100 points), and pain scores (0 to 10 points).

RESULTS

Both groups achieved significant improvement in the 2 FAAM measures, the SF-36 PCS score, and all of the pain measures at 48 months after surgey (p < 0.001). Mean improvements from baseline in patients undergoing TAA for the FAAM Activities of Daily Living, FAAM Sports, and SF-36 scores were at least 9 points, 8 points, and 3.5 points, respectively, which were higher than in those undergoing AA. Mean improvements in worst and average pain were at least 0.9 point higher in patients undergoing TAA than in those undergoing AA at 12, 24, and 36 months. These differences were attenuated by 48 months. For both treatments, all improvements from baseline to 24 months had been maintained at 48 months.

CONCLUSIONS

When both procedures are performed by the same group of surgeons, patients who undergo TAA or AA for end-stage ankle arthritis have significant improvement in overall function, ankle-specific function, and pain at 48 months after surgery, with better functional improvement in the TAA group.

LEVEL OF EVIDENCE

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

Comparison of Clinical Outcomes After Total Ankle Arthroplasty Between End-Stage Osteoarthritis and Rheumatoid Arthritis

BACKGROUND

Total ankle arthroplasty (TAA) is known to be a reliable operative option for end-stage rheumatoid arthritis. However, higher risk of postoperative complications related to chronic inflammation and immunosuppressive treatment is still a concern. With the use of a newer prosthesis and modification of anti-rheumatic medications, we compared clinical outcomes after TAA between patients with osteoarthritis and rheumatoid arthritis.

METHODS

Forty-five patients with end-stage osteoarthritis (OA group) and 19 with rheumatoid arthritis (RA group) were followed for more than 3 years after 3 component mobile-bearing TAA (Zenith^TM). Perioperative anti-rheumatic medications were modified using an established guideline used in total hip and knee arthroplasty. Clinical evaluations consisted of American Orthopaedic Foot & Ankle Society (AOFAS) scores, Foot and Ankle Outcome Score (FAOS), and Foot and Ankle Ability Measure (FAAM).

RESULTS

In the preoperative and postoperative evaluation at final follow-up, there were no significant differences in AOFAS, FAOS, and FAAM scores between 2 groups. Despite statistical similarity in total scores, the OA group showed significantly better scores in FAOS sports and leisure (mean, 57.4 ± 10.1) and FAAM sports activity (mean, 62.5 ± 13.6) subscales than those in the RA group (mean, 52.2 ± 9.8, P = .004; and 56.4 ± 13.2, P < .001, respectively). There were no significant differences in perioperative complication and revision rates between 2 groups.

CONCLUSION

Patients with end-stage ankle RA had clinical outcomes comparable to the patients with OA, except for the ability related to sports activities. In addition, there were no significant differences in early postoperative complication rates, including wound problem and infection.

LEVEL OF EVIDENCE

Level III, prognostic, prospective 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.

Differences in Gait and Stair Ascent After Total Ankle Arthroplasty and Ankle Arthrodesis

BACKGROUND

Ankle arthrodesis has historically been the standard of care for end-stage ankle arthritis; however, total ankle arthroplasty (TAA) is considered a reliable alternative. Our objective was to compare 3-dimensional foot and ankle kinetics and kinematics and determine the ankle power that is generated during level walking and stair ascent between TAA and ankle arthrodesis patients.

METHODS

Ten patients who underwent TAA with a modern fixed-bearing ankle prosthesis and 10 patients who previously underwent ankle arthrodesis were recruited. Patients were matched for age, sex, body mass index, time from surgery, and preoperative diagnosis. A minimum of 2-year follow-up was required. Patients completed instrumented 3D motion analysis while walking over level ground and during stair ascent. Between-group differences were assessed with a 2-tailed Mann-Whitney exact test for 2 independent samples.

RESULTS

Sagittal ankle range of motion (ROM) was significantly higher in the TAA group (21.1 vs 14.7 degrees, P = .003) during level walking. In addition, forefoot-tibia motion (25.3±5.9 degrees vs 18.6±5.1 degrees, P = .015) and hindfoot-tibia motion (15.4±3.2 degrees vs 12.2±2.5 degrees, P = .022) were significantly greater in the TAA group. During stair ascent, sagittal ankle ROM (25 vs 17.1 degrees, P = .026), forefoot-tibia motion (27.6 vs 19.6 degrees, P = .017), and hindfoot-tibia motion (16.8 vs 12 degrees, P = .012) was greater.

CONCLUSION

There were significant differences during level walking and stair ascent between patients with TAA and ankle arthrodesis. TAA patients generated greater peak plantarflexion power and sagittal motion within the foot and ankle compared to patients with an ankle arthrodesis. Further investigation should continue to assess biomechanical differences in the foot and ankle during additional activities of daily living.

LEVEL OF EVIDENCE

Level III, comparative study.

In vivo kinematics of fixed-bearing total ankle arthroplasty

BACKGROUND

A good recovery of the physiological mobility of the ankle is an indication of patients' satisfaction after total ankle arthroplasty, which does not generally match that of other consolidated procedures such as hip and knee replacement. The aim of this study was to investigate the kinematics of the Zimmer Total Metal Total Ankle (ZTMTA) during the different exercises.

METHODS

Fifteen patients with ZTMTA were enrolled in this study. The patients performed non-weightbearing flexion-extension, stair climbing and descending, and fluoroscopic images were taken to capture the ankle movements. A combined images/three-dimensional models method was used to perform a kinematic analysis.

RESULTS

Plantar-dorsiflexion resulted the main plane of movement, with the largest range of motion (ROM) of 23.3 ± 9.0° during flexion-extension. Inversion-eversion and adduction-abduction resulted lower than 10° in any trials.

CONCLUSIONS

In the investigated population, the ZTMTA allowed a good recovery of the mobility, with ROMs comparable to the healthy subjects.

Arthrodesis of the Foot or Ankle in Adult Patients with Congenital Clubfoot

Background

Although clubfoot that was corrected in childhood rarely recurs in adulthood, persistent deformities or arthritic pain may require further treatment during adulthood. Little evidence exists on the operative procedures utilized in adult clubfoot patients, who were previously treated for congenital clubfoot in childhood, for residual or recurrent deformity or pain.

Objective

The objective of this study is to characterize the types and frequencies of procedures utilized in adult clubfoot patients, who were previously treated for congenital clubfoot in childhood.

Methods

A two-pronged approach was employed to describe the operative procedures used in adult clubfoot patients. First, a literature review of all reported cases of operative treatment in adult clubfoot patients who were previously treated in childhood was performed. Second, an analysis of the operative treatments used in adult patients with a diagnosis of congenital clubfoot was conducted using a large, administrative claims database.

Results

In the literature review, arthrodesis was the most cited operative treatment and reported in four out of the eight studies included. Osteotomies were also reported in the literature. In the database analysis, 94 hindfoot arthrodesis procedures were identified in 73 patients, out of 1,198 adult patients in the database with a diagnosis of congenital clubfoot. Sixty-two patients out of 1,198 adult clubfoot patients received osteotomies. An insufficient number of total ankle arthroplasties were reported for further analysis.

Conclusions

Operative treatment in adult clubfoot patients who were treated for congenital clubfoot in childhood includes hindfoot arthrodesis and osteotomy procedures. Total ankle arthroplasty has not been reported in the literature for these patients.

Outcomes of Total Ankle Arthroplasty in Ankles with >20° of Coronal Plane Deformity

BACKGROUND

A preoperative severe coronal plane deformity of >20° has been considered a contraindication for total ankle arthroplasty. We aimed to evaluate whether outcomes of total ankle arthroplasty in ankles with severe coronal plane deformity (20° to 35° of varus or valgus) are comparable with those with moderate deformity (5° to 15° of varus or valgus).

METHODS

A total of 148 consecutive ankles (142 patients) that underwent primary total ankle arthroplasty using the HINTEGRA prosthesis were included. The overall mean follow-up duration was 74 months (range, 24 to 160 months). We divided all patients into 2 groups according to the preoperative coronal plane tibiotalar angle: the severe group (36 patients, 41 ankles) and the moderate group (106 patients, 107 ankles). Clinical and radiographic outcomes were analyzed for intergroup differences, and multivariable regression was used to adjust for baseline characteristics. Patients in each group showed similar characteristics in mean age, sex, mean body mass index, and median follow-up duration.

RESULTS

At a mean follow-up of 74 months, we found no significant intergroup difference in the Ankle Osteoarthritis Scale pain and disability score, American Orthopaedic Foot & Ankle Society ankle-hindfoot score, Short Form-36 Physical Component Summary score, visual analog scale pain score, or ankle range of motion (p > 0.05). However, the final tibiotalar angle, talar tilt angle, and number of outliers were greater in the severe group (p < 0.05). Complication rates did not show a significant difference between the 2 groups (p > 0.05). The overall survival probability of the implant was 91.3% (92.3% in the severe group and 90.7% in the moderate group) (p = 0.354).

CONCLUSIONS

Total ankle arthroplasty in ankles with preoperative severe coronal plane deformity showed satisfactory and comparable clinical outcomes without increasing complication rates relative to those with moderate deformity in the intermediate-term follow-up. Our results suggested that total ankle arthroplasty may be considered in ankles with deformity of >20°.

LEVEL OF EVIDENCE

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

Outcomes of Total Ankle Replacement, Arthroscopic Ankle Arthrodesis, and Open Ankle Arthrodesis for Isolated Non-Deformed End-Stage Ankle Arthritis

BACKGROUND

End-stage ankle arthritis is a disabling condition that has a similar effect on morbidity, pain, and loss of function to hip arthritis. We compared clinical outcomes of total ankle replacement (TAR) involving the HINTEGRA prosthesis (Integra LifeSciences), arthroscopic ankle arthrodesis (AAA), and open ankle arthrodesis (OAA) in patients with isolated, non-deformed end-stage ankle arthritis.

METHODS

Patients ≥18 years old who underwent TAR, AAA, or OAA from 2002 to 2012 with a minimum follow-up of 2 years were retrospectively identified from the Canadian Orthopaedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstruction Database. All patients had symptomatic COFAS Type-1 end-stage ankle arthritis without intra-articular or extra-articular deformity or surrounding joint arthritis. Clinical outcomes included the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36). Revision was defined as removal of 1 or both metal ankle prosthesis components for TAR and as reoperation for malposition, malunion, or nonunion for AAA and OAA.

RESULTS

Analysis included 238 ankles (88 TAR, 50 AAA, and 100 OAA) in 229 patients with a mean follow-up of 43.3 ± 18.5 months. The TAR group had more female patients (55%; p = 0.0318) and a higher mean age (p = 0.0005). Preoperative AOS pain, disability, and total scores were similar for all groups. SF-36 physical and mental component summary scores were similar across groups, both preoperatively and postoperatively. Improvement in AOS total score was significantly larger for TAR (34.4 ± 22.6) and AAA (38.3 ± 23.6) compared with OAA (25.8 ± 25.5; p = 0.005). Improvement in AOS disability score was also significantly larger for TAR (36.7 ± 24.3) and AAA (40.5 ± 26.4) compared with OAA (26.0 ± 26.2; p = 0.0013). However, the greater improvements did not meet the minimal clinically important difference. The TAR group underwent more reoperations than AAA and OAA groups (p < 0.0001). Revision rates were similar for all 3 groups (p = 0.262).

CONCLUSIONS

AAA and OAA resulted in comparable clinical outcomes to TAR in patients with non-deformed, COFAS Type-1 end-stage ankle arthritis. The rate of component revision in patients who underwent TAR was similar to the rate of revision for patients who underwent AAA or OAA; however, TAR patients underwent a greater number of additional procedures. Overall, AAA and TAR involving the HINTEGRA prosthesis were not significantly different surgical options in terms of short-term outcomes; patients should be counseled regarding higher reoperation rates for TAR.

LEVEL OF EVIDENCE

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

Clinical Outcomes of Total Ankle Arthroplasty With Total Talar Prosthesis

BACKGROUND

Total ankle arthroplasty (TAA) has been developed to treat patients with end-stage ankle osteoarthritis (OA). However, there is often difficulty in treating complicated pathologies such as ankle OA with subtalar joint OA and severe talar collapse. Therefore, this study aimed to explore the short-term results and complications of TAA with total talar prosthesis, known as combined TAA, as the new techniques to treat such complicated pathology.

METHODS

We examined postoperative results including ankle range of motion, Japanese Society for Surgery of the Foot (JSSF) scale, and complications. There were 22 patients (15 women), with mean follow-up of 34.9 (range, 24-53 months), and the mean age was 72 (range, 62-80) years. The main indications for combined TAA included osteoarthritis (18 patients), rheumatoid arthritis (3 patients), and talar osteonecrosis with osteoarthritis (one patient).

RESULTS

The mean range of motion improved from 4.0 to 14.4 degrees in dorsiflexion and from 23.8 to 32.0 degrees in plantarflexion. The JSSF scale improved from 50.5 to 91.5 points. Prolonged wound healing occurred in 3 patients, and medial malleolus fracture occurred in 4 patients.

CONCLUSION

Combined TAA was a reliable procedure for the treatment of not only ankle OA following avascular necrosis of talus but also of degeneration of both ankle and subtalar joints.

LEVEL OF EVIDENCE

Level IV, case series.

Comparative Analysis of Short-Term Postoperative Complications in Outpatient Versus Inpatient Total Ankle Arthroplasty: A Database Study

Ankle arthritis is a potentially debilitating disease, with approximately 50,000 cases diagnosed annually. One treatment option for these patients is total ankle arthroplasty (TAA). This procedure has historically been performed in the inpatient setting with a 1-2-night postoperative hospital stay. Outpatient surgeries are gaining popularity due to their cost effectiveness, decreased length of hospital stay, and convenience. Therefore it is important to evaluate the safety of specific procedures in the outpatient setting compared with the inpatient setting. This study evaluated the complication rates in inpatient versus outpatient TAA. It analyzed data from the National Surgical Quality Improvement Program for 591 patients who received TAA. Postoperative complication rates were compared between 66 outpatients and 535 inpatients. Frequencies of the following complications were analyzed: wound complications, pneumonia, hematologic complications (pulmonary embolism and deep vein thrombosis), renal failure, stroke, and return to the operating room within 30 days. Unadjusted direct comparisons of the cohorts revealed higher complication rates in the inpatient cohort. Inpatients had higher rates of superficial surgical site infections, deep surgical site infections, number of organ/space surgical site infections, pneumonia occurrences, and return to the operating room, but these differences were not significant. These results showed no significant increase in complication rates in outpatients compared to inpatients. Our results suggest that inpatient and outpatient TAA show similar complication rates. This suggests that outpatient TAA is safe and may be a superior option for certain populations. Further investigation is warranted to verify these conclusions.

Changes in the ankle muscles co-activation pattern after 5 years following total ankle joint replacement

BACKGROUND

The Hintegra® arthroplasty provides inversion-eversion stability, permits axial rotation, ankle flexion-extension, and improvements of the gait patterns are expected up to 12 months of rehabilitation. However, sensorimotor impairments are observed in ankle flexors/extensors muscles after rehabilitation, with potential negative effects on locomotion. Here we determined the timing and amplitude of co-activation of the tibialis anterior and medial gastrocnemius muscles during gait by assessing non-operated and operated legs of patients with total ankle replacement, 5 years after surgery.

METHODS

Twenty-nine patients (age: 58 [5.5] years, height: 156.4 [6.5] cm, body mass: 72.9 [6.5] kg, 10 men, and 19 women) that underwent Hintegra® ankle arthroplasty were included. Inclusion criteria included 5 years prosthesis survivorship. The onset and offset of muscle activation (timing), as well as the amplitude of activation, were determined during barefoot walking at self-selected speed by surface electromyography. The timing, percentage, and index of co-activation between the tibialis anterior and medial gastrocnemius were quantified and compared between non-operated and operated legs.

FINDINGS

The operated leg showed higher co-activation index and temporal overlapping between tibialis anterior and medial gastrocnemius during gait (p < 0.001).

INTERPRETATION

The neuromuscular changes developed during the process of degeneration do not appear to be restored 5 years following arthroplasty. The insertion of an ankle implant may restore anatomy and alignment but neuromuscular adaptations to degeneration are not corrected by 5 years following joint replacement.

Short-term Clinical and Radiographic Results of the Salto Mobile Total Ankle Prosthesis

BACKGROUND

The mobile-bearing Salto total ankle prosthesis has been reported to have promising outcomes. However, clinical reports on this prosthesis are few, and most have been published by the inventors and disclosed consultants.

METHODS

We retrospectively reviewed 59 patients who received Salto prosthesis unilaterally. The average follow-up was 35.9 (range, 6-56) months. Clinical and radiologic results were evaluated. Clinical results were evaluated according to visual analog scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, Ankle Osteoarthritis Scale (AOS) pain and disability score, and ankle range of motion (ROM) in dorsiflexion/plantarflexion. In the radiographic evaluation, we measured the tibial angle (TA), talar angle (TAL), tibial slope, and talocalcaneal angle (TCA) on weightbearing radiographs.

RESULTS

By the last follow-up, 7 of 59 patients (11.9%) had undergone reoperation, and 3 of 59 implants (5.1%) had been removed. The prosthesis survival was 94.9% (95% CI, 89.1%-100%). With any reoperation as the endpoint of follow-up, the clinical success rate was 88.1% (95% CI, 79.4%-96.9%). The mean postoperative visual analog scale score, AOFAS ankle-hindfoot score, and Ankle Osteoarthritis Scale pain and disability score improved significantly ( P < .001). The ankle range of motion also improved from preoperative 33.4 ± 16.6 to 40.3 ± 15.5 postoperatively ( P < .001); however, there was no statistically significant change in plantarflexion ( P = .243). Radiolucent areas and osteolysis were found in 28 (47.5%) and 27 (45.8%) patients, respectively. Heterotopic ossification was observed in 13 patients (22.0%).

CONCLUSIONS

In this series, early clinical and radiographic outcomes of this prosthesis were promising. We believe the early radiolucent lines were probably due to the gap at the implant and bone interface, and they disappeared at the time of osseous integration. However, longer follow-up is necessary to determine the long-term durability and survivorship of this implant, particularly given the high incidence of postoperative osteolysis.

LEVEL OF EVIDENCE

Level IV, case series.

Bone cyst formation after ankle arthroplasty may be caused by stress shielding. A numerical simulation of the strain adaptive bone remodelling

BACKGROUND

The history of total ankle arthroplasty (TAA) has different evolution steps to improve the outcome. The third generation implants show an overall 8-year survival rate up to 93%. The main reported reason for early failure of TAA is aseptic loosening, cyst formation is also frequently reported. The aim of the present study is to use the finite element (FE) method to analyze the adaptive bone remodeling processes, including cyst formation after TAA.

METHODS

Bone characteristics applied to the model corresponded to information obtained from computed tomography. Finite element models for the tibia and the talus were developed and implant components were virtually implanted.

RESULTS

The calculated total bone loss is 2% in the tibia and 17% in the talus. Cysts and areas of increased bone density were detectable dependent on prosthesis design in the tibia and talus.

CONCLUSION

Our FE simulation provides a theoretical explanation for cyst formation and increasing bone density depending on implant design. However, cysts are not mono-causal, histo-chemical reactions should also be considered. Further clinical studies are necessary to evaluate the relevance of cyst formation and therapeutic strategies.

Outcome of ankle arthrodesis and ankle prosthesis: a review of the current status

INTRODUCTION

In advanced stages of ankle osteoarthritis (OA), ankle arthrodesis (AA) or total ankle arthroplasty (TAR) may be necessary. Our purpose is to compare AA and total ankle replacement for the surgical management of end stage ankle OA.

SOURCES OF DATA

We conducted a literature search of PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar databases using the terms 'ankle' in combination with 'OA', 'arthrodesis', 'arthroplasty', 'joint fusion', 'joint replacement'. Studies where treatment was exclusively total ankle replacement or AA were excluded. Treatment characteristics and outcome parameters (overall postoperative outcome and complication rate) were reviewed.

AREAS OF AGREEMENT

When counseling patients who are considering their options with regard to ankle arthritis treatment, surgeons should determine on an individual basis which procedure is more suitable.

AREAS OF CONTROVERSY

TAR has become an accepted treatment for end-stage OA, but revision rates for TAR are significant higher than for AA (odds ratio 2.28 95% confidence interval [CI], 1.63-3.19; P < 0.0001).

GROWING POINTS

The results of TAA are gradually improving, but the procedure cannot yet be recommended for the routine management of ankle OA.

AREAS TIMELY FOR DEVELOPING RESEARCH

Although there is some evidence to support TAR to conserve ankle motion and offer improved function and decreased pain with high satisfaction rates, revision rates for TAR are significantly higher than revision rates for AA. Proper patient selection should be better addressed in future studies for successful treatment of end-stage ankle OA.

LEVEL OF EVIDENCE

Systematic review, level III.

Contact stresses, pressure and area in a fixed-bearing total ankle replacement: a finite element analysis

BACKGROUND

Mobile-bearing ankle implants with good clinical results continued to increase the popularity of total ankle arthroplasty to address endstage ankle osteoarthritis preserving joint movement. Alternative solutions used fixed-bearing designs, which increase stability and reduce the risk of bearing dislocation, but with a theoretical increase of contact stresses leading to a higher polyethylene wear. The purpose of this study was to investigate the contact stresses, pressure and area in the polyethylene component of a new total ankle replacement with a fixed-bearing design, using 3D finite element analysis.

METHODS

A three-dimensional finite element model of the Zimmer Trabecular Metal Total Ankle was developed and assembled based on computed tomography images. Three different sizes of the polyethylene insert were modeled, and a finite element analysis was conducted to investigate the contact pressure, the von Mises stresses and the contact area of the polyethylene component during the stance phase of the gait cycle.

RESULTS

The peak value of pressure was found in the anterior region of the articulating surface, where it reached 19.8 MPa at 40% of the gait cycle. The average contact pressure during the stance phase was 6.9 MPa. The maximum von Mises stress of 14.1 MPa was reached at 40% of the gait cycle in the anterior section. In the central section, the maximum von Mises stress of 10.8 MPa was reached at 37% of the gait cycle, whereas in the posterior section the maximum stress of 5.4 MPa was reached at the end of the stance phase.

DISCUSSION

The new fixed-bearing total ankle replacement showed a safe mechanical behavior and many clinical advantages. However, advanced models to quantitatively estimate the wear are need.

CONCLUSION

To the light of the clinical advantages, we conclude that the presented prosthesis is a good alternative to the other products present in the market.

Comparison of the outcome of total ankle arthroplasty for osteoarthritis with moderate and severe varus malalignment and that with neutral alignment

AIMS

The purpose of this study was to compare the clinical and radiographic outcomes of total ankle arthroplasty (TAA) in patients with pre-operatively moderate and severe arthritic varus ankles to those achieved for patients with neutral ankles.

PATIENTS AND METHODS

A total of 105 patients (105 ankles), matched for age, gender, body mass index, and follow-up duration, were divided into three groups by pre-operative coronal plane tibiotalar angle; neutral (< 5°), moderate (5° to 15°) and severe (> 15°) varus deformity. American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, a visual analogue scale (VAS), and Short Form (SF)-36 score were used to compare the clinical outcomes after a mean follow-up period of 51 months (24 to 147).

RESULTS

The post-operative AOFAS, VAS scores, range of movement and complication rates did not significantly differ among three groups. However, there was less improvement in the SF-36 score of the severe varus group (p = 0.008). The mean post-operative tibiotalar alignment was 2.6° (0.1° to 8.9°), 3.1° (0.1° to 6.5°) and 4.6° (1.0° to 10.6°) in the neutral, moderate and severe groups respectively. Although the severe varus group showed less corrected alignment than the neutral group, the mean tibiotalar angles of the three groups were within neutral alignment.

CONCLUSION

TAA for moderate and severe varus arthritic deformity showed similar satisfactory clinical and radiographic outcomes as those obtained by patients in the neutral group when post-operative neutral alignment was achieved. Cite this article: Bone Joint J 2017;99-B:1335-42.

Complex Total Ankle Arthroplasty

Total ankle arthroplasty is a viable surgical technique for the treatment of end-stage degenerative joint disease. With continued advancement in prosthetic design, refined surgical techniques, and improved outcomes, the indications for total ankle replacement have expanded to include cases of increasing complexity. With meticulous preoperative planning and exacting execution, many frontal plane deformities and cases of avascular necrosis can now be successfully addressed at the time of prosthesis implantation or in a staged procedure.

Patient selection for total ankle arthroplasty

Total ankle arthroplasty is a treatment option for end-stage osteoarthritis of the ankle, as is ankle arthrodesis. Many variables, including patient characteristics, are thought to influence clinical outcome and survival. As with any surgery, but especially with total ankle replacement (TAR), patient selection is considered critical for good (long-term) outcome. In this review, we summarize the available scientific evidence regarding patient characteristics and its influence on the results of TAR.

Accuracy assessment of measuring component position after total ankle arthroplasty using a conventional method

Background

This study was to assess the accuracy of measuring the tibial and talar components position and to investigate the outlier rate of each component and predisposing factors related to component malalignment after total ankle arthroplasty (TAA) using a conventional method.

Methods

One hundred fifty consecutive primary total ankle arthroplasty were performed using the three-component HINTEGRA prosthesis for ankle end-stage osteoarthritis. Radiographic analysis for the accuracy of component position in coronal and sagittal plane was conducted at postoperative 6 months. Additionally, the accuracy of component position was evaluated according to presence of preoperative deformity or joint incongruency.

Results

The mean postoperative coronal angles of the tibial and talar components (α and γ) were 91.9° and 91.3°. The mean postoperative sagittal angles of the tibial and talar components (β and δ angle) were 84.6° and 91.7°. In the coronal plane, 16 (10.7%) tibial components and 15 (10.0%) talar components showed outliers greater than 5°. In sagittal plane, 15 (10.0%) tibial components and 29 (19.3%) talar components showed outliers greater than 5°. There was no meaningful increase of the outlier rate regarding presence of preoperative deformity or joint incongruency.

Conclusions

In conventional method of TAA, the outlier rate of the tibial and talar components was about 10 to 20%, especially, the outlier rate of talar component in sagittal plane was up to 20%. Therefore, careful attention should be paid to implant the talar component in conventional TAA.

Management of Talar Component Subsidence

Component subsidence has been found to be the top complication that leads to failure of the total ankle arthroplasty (TAA). The cause of subsidence formation is unclear, and is multifactorial. Talar subsidence is more frequently met than tibial subsidence, and the subsequent big bone loss is demanding to handle. As a revision treatment option, neither a revision TAA nor a salvage ankle and/or hindfoot arthrodesis procedure is easy to perform or can obtain a definite outcome. The Salto XT can be used to treat most of the TAA systems available for use in the United States with acceptable short-term outcomes.

Arthroscopic Ankle Arthrodesis

Arthroscopic ankle arthrodesis is a cost-effective option for many patients with posttraumatic arthritis of the ankle joint. Rehabilitation is generally quicker than conventional open techniques, and rates of fusion are comparable or better than traditional open techniques. Unless the arthroscopic surgeon has considerable experience, the best results are seen in patients with very little deformity in the ankle joint.

Validity and reliability of ankle morphological measurements on computerized tomography-synthesized planar radiographs

Background

Clinical success of total ankle arthroplasty depends heavily on the available information on the morphology of the bones, often obtained from measurements on planar radiographs. The current study aimed to evaluate the intra-rater, inter-rater and inter-session reliability and the validity of radiograph-based measurements of ankle morphology, and to quantify the effects of examiner experience on these measurements.

Methods

Twenty-four fresh frozen ankle specimens were CT scanned, data of which were used to reconstruct 3D volumetric bone models for synthesizing 2D radiographs. Two orthopaedic surgeons with different levels of clinical experience identified twenty landmarks five times on each of the synthesized sagittal and coronal radiographs and repeated the test on a subsequent day within 5 days. The landmarks were used to calculate fourteen morphological parameters. The two-way mixed-effects (ICC3,1), two-way random-effects (ICC2,k) and two-way random-effects (ICC3,k) models were used, respectively, to assess the intra-rater, inter-rater and inter-session reliability of measurements. The validity of the measurements for each examiner was assessed by comparing them with gold standard values obtained from the 2D radiographs projected from the 3D volumetric models using Pearson’s correlation analysis and Bland and Altman plots, and the differences were defined as the measurement errors.

Results

Most of the morphological parameters were of good to very good intra-rater, inter-session and inter-rater reliability for both examiners (ICC > 0.61). Experience appeared to affect the inter-rater and inter-session reliability, the senior examiner showing greater inter-session ICC values than the junior examiner. Most of the tibial parameters had moderate to excellent correlations with the corresponding gold standard values but were underestimated by both examiners, in contrast to most of the talar parameters that were overestimated and had only poor to fair correlations.

Conclusions

Most of the morphological parameters of the ankle can be estimated from radiographs with good to very good intra-rater, inter-session and inter-rater reliability, for both clinically experienced and less experienced examiners. Clinical experience helped increase the reliability of repeated evaluations after a longer interval, such as in a follow-up assessment. It is suggested that critical clinical decisions based on repeated morphology measurements should be made by more experienced surgeons or after appropriate training.

Intraoperative Radiation Exposure During Revision Total Ankle Replacement

Intraoperative C-arm image intensification is required for primary total ankle replacement implantation. Significant radiation exposure has been linked to these procedures; however, the radiation exposure during revision total ankle replacement remains unknown. Therefore, we sought to evaluate the radiation exposure encountered during revision total ankle replacement. The data from 41 patients were retrospectively analyzed from a prospective database: 19 Agility(™) to Agility(™); 4 Agility(™) to Custom Agility(™); 9 Agility(™) to INBONE(®) II; 5 Agility(™) to Salto Talaris(®) XT; 2 Scandinavian Total Ankle Replacement Prosthesis to Salto Talaris(®) XT; and 2 INBONE(®) I to INBONE(®) II revision total ankle replacements were performed. Two broad categories were identified: partial revision (Agility(™) to Agility(™), Agility(™) to Custom Agility(™), INBONE(®) I to INBONE(®) II) and complete conversion (Agility(™) to INBONE(®) II, Agility(™) to Salto Talaris(®) XT, Scandinavian Total Ankle Replacement Prosthesis to Salto Talaris(®) XT). The mean radiation exposure per case was significant at 3.49 ± 2.21 mGy. Complete conversions, specifically Agility(™) to INBONE(®) II, exhibited the greatest radiation exposure and C-arm time. Revision implant selection and revision type (complete or partial) directly contributed to radiation exposure. Accordingly, revision systems requiring less radiation exposure are preferable. Surgeons should strive to minimize intraoperative complications and limit additional procedures to those necessary, because both lead to additional radiation exposure.

Computed Tomographic Evaluation of Joint Geometry in Patients With End-Stage Ankle Osteoarthritis

BACKGROUND

Deformation of the talus and the distal tibia can be frequently observed during ankle joint osteoarthritis (OA). The aim of this study was to objectify these morphologic changes. We hypothesized that a flattening of the talus and a broadening of the distal tibia surface occurs in end-stage OA of the ankle joint.

METHODS

Twenty-seven computed tomography (CT) ankle joint examinations of unilateral ankle OA were matched by sex and age with 27 CT examinations of healthy ankle joints. Three-dimensional reformatting and measurements were performed with geometry analysis software. The following parameters were assessed: sagittal radius of the talus, talus height, and mediolateral and anteroposterior width of the distal tibial joint surface.

RESULTS

Medial, midsagittal, and lateral sagittal arc radii of osteoarthritic tali were significantly larger compared to tali of controls. There was a statistically significant difference in the height of the osteoarthritic talar dome in the medial and in the lateral frontal segment and in the medial central segment compared to tali of controls. The anteroposterior width and the sagittal curvature of the distal tibia was significantly larger in OA ankles than in the control group. The mediolateral measurements were comparable across both groups.

CONCLUSION

Flattening of the talus appears to be more pronounced in the frontal aspect of the talus. The distal tibia broadens anteroposteriorly. These findings may contribute to better understanding of ankle OA development.

LEVEL OF EVIDENCE

Level III, retrospective comparative cohort study.

Influence of Ankle Position and Radiographic Projection Angle on Measurement of Supramalleolar Alignment on the Anteroposterior and Hindfoot Alignment Views

BACKGROUND

Using digitally reconstructed radiographs (DRRs), we determined how changes in the x-ray beam projection angle from the horizon, tibiotalar joint angle, and axial rotation of the foot influenced measurements of the medial distal tibial angle (MDTA) on the anteroposterior (AP) and hindfoot alignment views (HAV).

METHODS

Seven cadaver foot-ankle specimens were scanned by computed tomography (CT) at fixed tibiotalar joint positions, ranging from 15 degrees of dorsiflexion to 25 degrees of plantarflexion. DRRs were created from each CT scan to simulate alterations in the horizontal projection angle (0 to 25 degrees) and foot axial rotation (-30 to 30 degrees). The MDTA was measured on each DRR and compared with that quantified on the baseline HAV and AP view.

RESULTS

Altering the horizontal projection angle by ≥5 degrees and >10 degrees significantly altered the MDTA for the AP view and the HAV, respectively. Shifting dorsiflexion and plantarflexion caused minor changes in the MDTA that were only statistically significant for the HAV. Axial rotation significantly changed the MDTA on both views, but deviations were more pronounced for the HAV.

CONCLUSIONS

Compared with the HAV, the MDTA on the AP view was less sensitive to changes in foot-ankle position. However, increasing the tilt of the x-ray beam from the horizon altered the MDTA on the AP view substantially.

CLINICAL RELEVANCE

To avoid misinterpretation of the MDTA, we recommend using the AP view to quantify supramalleolar alignment as it is less sensitive to changes in positioning of the foot-ankle. When acquiring an AP film, the x-ray beam should be directed along the horizon to ensure consistent assessment of the MDTA across patients.

Arthroscopic Management of Complications Following Total Ankle Replacement

There is great potential of managing the complications of total ankle replacement arthroscopically and endoscopically, and these procedures can be summarized into 3 groups. Group 1 includes procedures of the ankle joint proper with close proximity to the articular components of the total ankle replacement. Group 2 includes procedures of the tibia and talus with close proximity to the nonarticular parts of the total ankle replacement. Group 3 includes procedures that are away from the total ankle replacement. However, these remain master arthroscopist procedures and should be performed by foot and ankle surgeons who perform them with regularity.

Management of Osseous and Soft-Tissue Ankle Equinus During Total Ankle Replacement

Obtaining functional alignment of a total ankle replacement, including physiologic sagittal plane range of motion, is paramount for a successful outcome. This article reviews the literature on techniques available for correction of osseous and soft-tissue equinus at the time of index total ankle replacement. These techniques include anterior tibiotalar joint cheilectomy, posterior superficial muscle compartment lengthening, posterior ankle capsule release, and release of the posterior portions of the medial and lateral collateral ligament complexes. The rationale for these procedures and the operative sequence of events for these procedures are presented.

Mid- to Long-term Clinical Outcome and Gait Biomechanics After Realignment Surgery in Asymmetric Ankle Osteoarthritis

BACKGROUND

Joint-preserving, realignment surgical procedures have gained increasing popularity as treatment of asymmetric early- and mid-stage ankle osteoarthritis. The aim of the present study was to quantify bilateral gait biomechanics in patients who underwent ankle realignment surgery by supramalleolar osteotomies.

METHODS

Eight patients, a minimum of 7 years after realignment surgery, and 8 healthy controls were included in this study. Three-dimensional instrumented gait analysis was used to assess spatiotemporal parameters, bilateral joint angles, and moments. Furthermore, a clinical evaluation on pain, ankle function, and quality of life was performed.

RESULTS

Compared with the healthy controls, the patients walked more slowly, had a smaller sagittal hindfoot range of motion on their affected leg, and had a lower peak ankle dorsiflexion moment (P < .05). There were no significant differences compared with controls for the ranges of motion in the foot segments of the nonaffected foot and for the knee and hip joint ranges of motion and peak moments of both legs. Additionally, patients and controls did not differ in the quality of life score. However, in the pain subscore, the patients reported significantly more pain than the healthy persons.

CONCLUSION

Despite different gait biomechanics of the affected foot after ankle realignment surgery, the quality of life for patients was comparable to that of healthy controls. Therefore, supramalleolar osteotomies should be considered as a promising treatment option in patients with asymmetric non-end-stage ankle osteoarthritis.

LEVEL OF EVIDENCE

Level III, comparative study.

Incidence of revision after primary implantation of the Salto ® mobile version and Salto Talaris ™ total ankle prostheses: a systematic review

The incidence of revision of total ankle replacement prostheses remains unclear. We undertook a systematic review to identify the material relating to the incidence of revision after implantation of the Salto(®) mobile version and Salto Talaris™ total ankle prostheses. Studies were eligible for inclusion only if they had involved primary total ankle replacement with these prostheses and had included the incidence of revision. Eight studies involving 1,209 Salto(®) mobile version prostheses, with a weighted mean follow-up period of 55.2 months, and 5 studies involving 212 Salto Talaris™ total ankle prostheses, with a weighted mean follow-up period of 34.9 months, were included. Forty-eight patients with Salto(®) mobile version prostheses (4%) underwent revision, of whom 24 (70.5%) underwent ankle arthrodesis, 9 (26.5%) metallic component replacement, and 1 (3%) below-the-knee amputation. Five (2.4%) Salto Talaris™ total ankle prostheses underwent revision (3 metallic component replacement and 2 ankle arthrodeses). Restricting the data to the inventor, design team, or disclosed consultants, the incidence of revision was 5.2% for the Salto(®) mobile version and 2.6% for the Salto Talaris™ total ankle prostheses. In contrast, data that excluded these individuals had an incidence of revision of 2.8% for the Salto(®) mobile version and 2.0% for the Salto Talaris™ total ankle prostheses. We could not identify any obvious difference in the etiology responsible for the incidence of revision between these mobile- and fixed-bearing prostheses. The incidence of revision for the Salto(®) mobile version and Salto Talaris™ total ankle prostheses was lower than those reported through systematic review for the Agility™ and Scandinavian Total Ankle Replacement™ systems without obvious selection (inventor) or publication (conflict of interest) bias.

Intermediate-term follow-up after ankle distraction for treatment of end-stage osteoarthritis

BACKGROUND

Treatment of end-stage ankle osteoarthritis remains challenging, especially in young patients. Initial reports have shown early benefits of joint distraction for the treatment of ankle osteoarthritis. We report the five to ten-year results of a previously described patient cohort following ankle distraction surgery.

METHODS

All thirty-six patients who had undergone ankle distraction surgery between December 2002 and October 2006 were contacted. Patients were evaluated by a clinical investigator and completed the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) surveys. Radiographs as well as computed tomography and magnetic resonance imaging scans of the ankles were obtained at the follow-up visits.

RESULTS

Twenty-nine patients (81%) were followed for a minimum of five years (mean and standard deviation, 8.3 ± 2.2 years). Sixteen (55%) of the twenty-nine patients still had the native ankle joint whereas thirteen patients (45%) had undergone either ankle arthrodesis or total ankle arthroplasty. Positive predictors of ankle survival included a better AOS score at two years (hazard ratio [HR] = 0.048, 95% confidence interval [CI] = 0.0028 to 0.84, p = 0.04), older age at surgery (HR = 0.91, 95% CI = 0.83 to 0.99, p = 0.04), and fixed distraction (HR = 0.094, 95% CI = 0.017 to 0.525, p < 0.01). Radiographs and advanced imaging revealed progression of ankle osteoarthritis at the time of final follow-up.

CONCLUSIONS

Ankle function following joint distraction declines over time. Patients should be well informed of the commitment that they must make during the treatment period as well as the long-term results after surgery.

Investigating the relationship between ankle arthrodesis and adjacent-joint arthritis in the hindfoot: a systematic review

BACKGROUND

Ankle arthrodesis traditionally has been regarded as the treatment of choice for many patients with end-stage ankle arthritis. However, a major reported risk of ankle arthrodesis is adjacent-joint degeneration. There are conflicting views in the literature as to the causative link between ankle arthrodesis and progression to adjacent-joint arthritis. Recent studies have challenged the causative link between arthrodesis and adjacent-joint arthritis, purporting that preexisting adjacent-joint arthritis is present in many patients. The aim of the present study was to systematically review the available literature to determine if there is sufficient evidence to support either hypothesis.

METHODS

A literature search of the EMBASE and PubMed/MEDLINE databases (1974 to present) was performed. A total of twenty-four studies were included for review. The studies were reviewed, and the relevant information was extracted, including research methodology, postoperative outcomes in the adjacent joints of the foot, and whether pre-arthrodesis radiographs and medical records were available for analysis.

RESULTS

The twenty-four manuscripts included eighteen clinical studies, five biomechanical studies, and one gait-analysis study. The majority of biomechanical studies showed altered biomechanics in the fused ankle; however, there was no clear consensus as to whether these findings were causes of adjacent-joint arthritis. In studies assessing clinical outcomes, the reported prevalence of subtalar joint arthritis ranged from 24% to 100% and the prevalence of talonavicular and calcaneocuboid arthritis ranged from 18% to 77%. Correlation between imaging findings of arthritis in adjacent joints and patient symptoms was not established in a number of the clinical studies reviewed.

CONCLUSIONS

There is no true consensus in the literature as to the effects of ankle arthrodesis on biomechanics or whether ankle arthrodesis leads to adjacent-joint arthritis. Similarly, a correlation between postoperative imaging findings and clinical presentation in this cohort of patients has not been conclusively demonstrated.

Anatomic total talar prosthesis replacement surgery and ankle arthroplasty: an early case series in Thailand

Little is known about specific outcomes and early experiences of total talar prosthesis replacement surgery in the current literature, and ankle arthroplasty in Southeast Asia. This study reported on four patients with talar loss or ankle arthritis. Patients were treated with a custom total talar prosthesis (anatomic-metallic version) replacement (TPR, n=1) or with total ankle replacement (TAR, n=3). Baseline data, including Visual-Analog-Scale Foot and Ankle (VAS-FA) and Quality of Life scores via Short-Form-36 (SF-36), were collected for all patients. Mean follow-up time was 7.6 months. From preoperative to postoperative, VAS-FA score increased from 6.0 to 57.5, and SF-36 score increased from 19.3 to 73.7 in a patient with TPR. Mean VAS-FA scores increased from 51.5±15.6 to 85.7±4.7 (P=0.032), and mean SF-36 scores tended to increase from 65.2±13.3 to 99.3±1.2 (P=0.055) in TAR group. This study is the first report of anatomic-metallic TPR which appears to provide satisfactory outcomes for treatment of talar loss at a short-term follow-up. TAR also provides acceptable results for treatment of ankle arthritis at this point.

Continuous Infragluteal Sciatic Nerve Block for Postoperative Pain Control After Total Ankle Arthroplasty

Continuous peripheral nerve blocks (CPNB) for postoperative pain control are being used more frequently for total ankle arthroplasty. The purpose of this study was to compare the amount of opioid analgesia used in patients with an infragluteal CPNB to that of patients with no CPNB for postoperative pain management after total ankle replacement. A retrospective cohort study was performed on 78 consecutive patients who had a total ankle arthroplasty from October 2006 to June 2013. The primary outcome measure was opioid analgesia use in the first 48 hours postoperatively. The mean postoperative narcotic use in oral morphine equivalents was 64.6 mg in the CPNB group compared to 129.6 mg in the no CPNB group (P < .001). Using an infragluteal CPNB as a means of postoperative pain control in patients undergoing a total ankle replacement is associated with significantly decreased opioid use compared to patients receiving no CPNB.

LEVELS OF EVIDENCE

Therapeutic, Level IV, case series.

Trends in treatment of advanced ankle arthropathy by total ankle replacement or ankle fusion

BACKGROUND

Total ankle replacement (TAR) and ankle fusion (AF) are the 2 major operative options for treatment of advanced ankle arthropathy; there is, however, no large epidemiologic study comparing nationwide trends of these 2 procedures. The current study used a nationwide database to compare epidemiologic profiles of TAR and AF.

METHODS

Data collected for the Nationwide Inpatient Sample (NIS) from 2000 to 2010 were reviewed. Procedures were identified by searching for ICD-9-CM codes 81.11 (AF) and 81.56 (TAR). Patients' demographics and comorbidities, geographic distribution, and cost of procedures were compared.

RESULTS

The NIS analysis identified 2666 TAR and 16 419 AF cases which was extrapolated to 13 145 TAR and 80 426 AF nationwide. Spearman's ρ showed an increase in the number of AF per year while the number of TAR cases remained relatively flat per year until 2006, after which there was a steady increase in the number of TAR performed. Patients receiving a TAR tended to be older, female, and white. Patients who underwent AF were more likely to be obese or diabetic than TAR patients. Both TAR and AF were performed more frequently in private urban hospitals through 2007. However, in 2010, the number of TAR procedures was greater in academic centers compared to private urban hospitals.

CONCLUSIONS

Despite recent increases in the number of TAR implanted, AF was still performed more than 6 times more frequently for advanced ankle arthropathy. A trend was demonstrated toward an increasing number of TAR being implanted in academic centers, and in patients with more underlying comorbidities than was previously seen.

LEVEL OF EVIDENCE

Level II, prognostic study.

Biomechanics of the natural, arthritic, and replaced human ankle joint

The human ankle joint complex plays a fundamental role in gait and other activities of daily living. At the same time, it is a very complicated anatomical system but the large literature of experimental and modelling studies has not fully described the coupled joint motion, position and orientation of the joint axis of rotation, stress and strain in the ligaments and their role in guiding and stabilizing joint motion, conformity and congruence of the articular surfaces, patterns of contact at the articular surfaces, patterns of rolling and sliding at the joint surfaces, and muscle lever arm lengths.

The present review article addresses these issues as described in the literature, reporting the most recent relevant findings.