Revision rates after total ankle arthroplasty in sample-based clinical studies and national registries

The INVISION Talar Component in Revision Total Ankle Arthroplasty: Analysis of Early Outcomes

INTRODUCTION

Launched in 2018 for revision total ankle arthroplasty (rTAA), the INVISION talar component addresses subsidence when poor talar bone stock is present. Due to the recency of the market-availability of the INVISION, studies evaluating its efficacy are lacking. This study presents the first analysis of early-term outcomes of patients undergoing rTAA with the INVISION talar component.

METHODS

This was a single-center, retrospective review of 28 patients undergoing rTAA with the INVISION talar component and INBONE II tibial component performed between 2018 and 2022. Data on preoperative characteristics, postoperative complications, secondary procedures, and survivorship were collected. The primary outcome measures were rates of major complications, re-operation, and implant failure. Secondary outcomes included post-operative changes in varus and valgus alignment of the tibia and talus.

RESULTS

The most common secondary procedures performed with rTAA were medial malleolus fixation (n = 22, 78.6%) and gastrocnemius recession (n = 14, 50%). Overall, 10.7% (n = 3) of patients underwent reoperation and 14.3% (n = 4) suffered major complications. Incidence of implant failure was 10.7% (n = 3). All reoperations were caused by infection. Mean varus alignment of the tibia and talus improved from 4.07 degrees and 4.83 degrees to 1.67 degrees and 1.23 degrees, respectively. Mean valgus alignment of the tibia and talus improved from 3.67 degrees and 4.22 degrees to 2.00 degrees and 2.32 degrees, respectively.

CONCLUSIONS

In a series of 28 patients undergoing rTAA with the INVISION talar component, we discovered comparatively low rates of reoperation, major complication, and implant failure (10.7%, 14.3%, and 10.7%). The INVISION system appears to have a reasonable safety profile, but further studies evaluating long-term outcomes are required to assess the efficacy of the INVISION system.

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.

The use of a 3D printed titanium implant for arthrodesis in the management of large osseous defects in the ankle

BACKGROUND

Large osseous defects (LOD) in the ankle occur because of multiple aetiologies. Advancement in 3-dimensional (3D) printing technologies has led to the use of custom implants and instrumentation their management. A 3D printed patient-specific porous titanium cage which allows for peripheral osteo-integration and autogenous bone-grafting could be an ideal implant in these cases.

METHODS

Retrospective review of a multi-centre, multi-surgeon consecutive cohort of patients requiring either TTC or AA for a large osseous defect between June 2019 - August 2020. A custom titanium prosthesis was 3D-printed according to CT measurements for implantation.

RESULTS

Mean follow up was 19.5 months (range 12-24 months). Plain radiographs and CT scans at 12 months confirmed osseointegration (stability) in 11of 13 patients (84%). Two patients developed late infection, one requiring revision surgery.

CONCLUSIONS

3D-Printed titanium implants in the management of LODs in the ankle offer a comparable success rate to other reported procedures, with unlimited geometric possibilities in the design allowing for accurate length correction. Their structural stability may offer an advantage over conventional bone graft techniques and limits the amount of bone-graft required.

LEVELS OF EVIDENCE

LOE III.

[The German Association for Foot and Ankle (D.A.F.) registry on treatment of end-stage total ankle arthritis-what is its clinical impact?]

Initially established as a voluntary prosthesis register for total ankle replacement, the registry now enables analysis of revisions, complications, and clinical and functional outcomes-including patient-reported outcome measures-based on a period spanning more than 10 years. To allow analyses of the outcomes of ankle arthrodesis and supramalleolar osteotomies for treatment of end-stage arthritis in the future, the registry was extended by structured capturing of these procedures in 2018. While descriptive and analytical statistical evaluations of total ankle replacement are already possible today, the number of datasets on arthrodesis and supramalleolar osteotomies is still too small to support these analyses or comparative evaluations.

Soft-Tissue Reconstruction of Complicated Total Ankle Arthroplasty

BACKGROUND

Total ankle arthroplasty (TAA) is a popular modality to treat end-stage arthritis or internal ankle derangement. Unfortunately, failure rates remain undesirably high, with severe complications, including prosthesis failure, ankle fusion, and amputation. The importance of a stable soft-tissue envelope for coverage of implant compromise has been previously described, but the predictive factors for successful salvage of complicated TAA remain poorly understood.

METHODS

A retrospective review was conducted of patients requiring soft-tissue reconstruction following TAA wound complications. Patient demographics, history, microbiological data, reconstructive approach, and outcomes data were collected. Statistical analysis was used to abstract factors associated with unsuccessful prosthetic salvage.

RESULTS

In all, 13 patients met inclusion criteria: 8 (61.5%) achieved prosthetic salvage, and 5 (38.5%) failed. The majority (90.9%) of patients presented with infected joints. Reconstructive techniques included skin grafts, dermal substitutes, locoregional flaps, and free tissue transfer. Successful prosthetic salvage was associated with shorter time intervals between wound diagnosis and index reconstructive surgical intervention (median: 20 days for salvage vs 804 days for failure; P = .014). Additionally, salvage was associated with reduced time from the index orthopaedic/podiatric surgical intervention to the index reconstructive surgery procedure (12 vs 727 days; P = .027).

CONCLUSION

The prognosis of complicated TAA requiring soft-tissue reconstruction remains poor, especially in patients who present with infected joints. Several reconstructive techniques, ranging from simple skin grafts to complex free tissue transfers, can be used successfully. Early intervention to achieve soft-tissue coverage is crucial in maximizing salvage rates in the setting of complicated and infected TAA.

LEVEL OF EVIDENCE

Level IV.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

IV.

Ten-year revision rates of contemporary total ankle arthroplasties equal 22%. A meta-analysis

BACKGROUND

The National Institute for Health and Care Excellence criterion for hip replacements is a (projected) revision rate of less than 5% after 10 years. No such criterion is available for ankle prostheses. The objective of the current study is to compare survival rates of contemporary primary ankle prostheses to the hip-benchmark.

METHODS

The PRISMA methodology was used. Eligible for inclusion were clinical studies reporting revision rates of currently available primary total ankle prostheses. Data was extracted using preconstructed forms. The total and prosthesis-specific annual revision rate was calculated.

RESULTS

Fifty-seven articles of eight different ankle prostheses were included (n = 5371), totaling 513 revisions at an average 4.6 years of follow-up. An annual revision rate of 2.2 was found (i.e. an expected revision rate of 22% at 10 years).

CONCLUSIONS

The expected 10-year revision rate of contemporary ankle prostheses is lower than the current benchmark for hip prostheses.

CT Scan Assessment and Functional Outcome of Periprosthetic Bone Grafting After Total Ankle Arthroplasty at Medium-term Follow-up

BACKGROUND

Periprosthetic cysts can occur in up to 95% of total ankle arthroplasties (TAA) and have been correlated with implant failure. The aim of this study was to determine the clinical and radiologic outcomes, using computed tomographic (CT) scan, after periprosthetic cyst bone grafting and assess for the minimum cyst size that should be grafted.

METHODS

A retrospective review was performed of all TAA procedures performed between 2007 and 2014 (n=93). A CT scan was done to assess cyst size and operative planning. Eight patients with 9 periprosthetic cysts larger than 1.75 cm³ were grafted and specimens sent for histology. The mean time to bone grafting was 7.3 (3.8-9.5) years. Functional outcome was assessed using the American Orthopaedic Foot & Ankle Society ankle score, visual analog scale, and Self-reported Foot and Ankle Score. A CT scan was performed at follow-up to assess graft incorporation and cyst size progression. The mean time to CT scan post grafting was 3.0 (0.7-4.7) years.

RESULTS

There was no implant malalignment identified and no differences in the pre- and postoperative functional scores. Preoperatively cysts had a mean volume of 8.16 (2.04-14.03) cm³. The mean percentage incorporation was 89% (69%-100%). Eight of the grafted cysts were considered successful on CT, with the ninth having 69% incorporation. Five cysts were not grafted, as they were below 1.75 cm³, and remained the same size or had minimal enlargement.

CONCLUSION

The satisfactory results in this small cohort suggests that prophylactic bone grafting may extend implant survival. We recommend that periprosthetic cysts greater than 1.75 cm³ be prophylactically bone grafted, and that cysts smaller than 1.75 cm³ be monitored for progression in size.

LEVEL OF EVIDENCE

Level IV, Case Series.

Ankle Arthritis Networking: Getting the right treatment to the right patient first time

End stage ankle joint arthritis is a debilitating condition. Surgical treatment, most commonly ankle arthrodesis or fusion, can be highly effective. The authors outline the nature and prevalence of ankle arthritis and show that the frequency of each type of procedure varies geographically. They present data supporting the hypothesis that units performing ankle replacement more frequently tend to have better outcomes, both clinically and financially. Adoption of country-wide Ankle Arthritis Networks is proposed, ensuring that every patient seeing a foot and ankle orthopaedic surgeon has potential access to all treatment options whether their surgeon chooses to perform replacement or not. The case is made that establishment of Ankle Arthritis Networks will avoid the need for units to perform a low number of replacements per year, homogenise treatment availability across the country and enables the right patient to receive the right treatment first time. LEVEL OF EVIDENCE: IV.

Two-Year Revision Rates in Total Ankle Replacement Versus Ankle Arthrodesis

The aim of this study was to compare outcomes between total ankle replacement (TAR) and ankle arthrodesis (AA) for ankle osteoarthritis using real-world data.

Analysis of early failure rate and its risk factor with 2157 total ankle replacements

The failure rate of TAA is still higher than that of other joint replacement procedures. This study aimed to calculate the early failure rate and identify associated patient factors. Data from the Korean Health Insurance Review and Assessment Service database from 2009 to 2017 were collected. We evaluated patients who had TAA as a primary surgical procedure. Early failure was defined as conversion to revision TAA or arthrodesis after primary TAA within five years. Patients with early failure after primary TAA were designated as the "Failure group". Patients without early failure and who were followed up unremarkably for at least five years after primary TAA were designated as the "No failure group". Overall, 2157 TAA participants were included. During the study period, 197 patients developed failure within five years postoperatively, for an overall failure rate of 9.1%. Significant risk factors for early failure were history of chronic pulmonary disease, diabetes, peripheral vascular disease, hyperlipidemia, dementia, and alcohol abuse. A significant increase of odds ratio was found in patients with a history of dementia, chronic pulmonary disease, and diabetes. Surgical indications and preoperative patient counseling should consider these factors.

12-year survival analysis of 322 Hintegra total ankle arthroplasties from an independent center

Background and purpose - Total ankle arthroplasties (TAAs) have larger revision rates than hip and knee implants. We examined the survival rates of our primary TAAs, and what different factors, including the cause of arthritis, affect the success and/or revision rate.Patients and methods - From 2004 to 2016, 322 primary Hintegra TAAs were implanted: the 2nd generation implant from 2004 until mid-2007 and the 3rd generation from late 2007 to 2016. A Cox proportional hazards model evaluated sex, age, primary diagnosis, and implant generation, pre- and postoperative angles and implant position as risk factors for revision.Results - 60 implants (19%) were revised, the majority (n = 34) due to loosening. The 5-year survival rate (95% CI) was 75% (69-82) and the 10-year survival rate was 68% (60-77). There was a reduced risk of revision, per degree of increased postoperative medial distal tibial angle at 0.84 (0.72-0.98) and preoperative talus angle at 0.95 (0.90-1.00), indicating that varus ankles may have a larger revision rate. Generation of implant, sex, primary diagnosis, and most pre- and postoperative radiological angles did not statistically affect revision risk.Interpretation - Our revision rates are slightly above registry rates and well above those of the developer. Most were revised due to loosening; no difference was demonstrated with the 2 generations of implant used. Learning curve and a low threshold for revision could explain the high revision rate.

Revision Surgery for Failed Total Ankle Replacement

Revision surgery for failed total ankle replacement is a challenge to the revision surgeon. Deformity, presence of infection, segmental bone defects, patient comorbidities, and soft tissue compromise all are significant considerations when determining appropriate procedures. Revision total ankle replacement, explant and fusion with or without lengthening, use of a trabecular metal cage, placement of an antibiotic cement spacer, grafting, and amputation all are viable options to treat patients with failed ankle arthroplasty.

Total Ankle Arthroplasty Survival and Risk Factors for Failure

BACKGROUND

Total ankle arthroplasty (TAA) is an increasingly selected treatment for end-stage ankle arthritis; however, failure and revision of the tibial and talar components remains an issue. Although multiple risk factors have been shown to contribute to early component revision, no study has looked at combining such risk factors into a predictive model that could potentially decrease revision rates and improve implant survival. This study aimed to develop a predictive model for TAA failure based on patient characteristics, patient-reported outcomes (PROs), and immediate postoperative radiographs.

METHODS

A retrospective review of a single-site ankle arthritis database was conducted. All patients with current-generation ankle replacements including the Hintegra and Infinity prostheses implanted between 2004 and 2015 and with complete postoperative radiographs taken between 6 and 12 weeks postoperatively were included. Eight coronal and sagittal radiographic parameters were assessed and performed twice by 2 independent orthopedic surgeons on included TAAs. These radiographic parameters were then analyzed in association with patient demographics and PRO. Advanced statistical methods including survival analysis were used to construct a predictive model for TAA survival. A total of 107 patients were included and analyzed with a median clinical follow-up of 49 months (minimum 24 months).

RESULTS

A predictive model was created, with 4 parameters identified as being statistically associated with TAA metal-component revision: diabetes mellitus, poor baseline Ankle Osteoarthritis Scale (AOS) score, excessively dorsiflexed talar component, and an anteriorly/posteriorly translated talus relative to the tibial axis. The presence of 3 parameters predicted TAA survival of 0.60 whereas presence of all 4 parameters predicted survival of only 0.13 in the period studied.

CONCLUSION

Our predictive model is based on a combination of patient factors, PROs, and radiographic TAA alignment. We believe it can be used by surgeons to predict failure in their TAA patients, thereby optimizing postoperative outcomes by improving patient selection and modifiable outcome-specific parameters.

LEVEL OF EVIDENCE

Level III, retrospective cohort study using prospectively collected data.

Total ankle arthroplasty and national registers: What is the impact on scientific production?

PURPOSE

The purpose of this systematic review was to analyze clinical studies on total ankle replacement (TAR) whose data were extracted from national registers.

METHODS

A systematic review of the literature, to identify all studies reporting outcomes after TAR, was performed. Two independent investigators performed the research using MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase and Cochrane Databases (1950 to December 2017). The search terms used were "total ankle replacement" or "total ankle arthroplasty" AND "register" or "registers" or "registry" or "registries" or "national registry" or "national register".

RESULTS

Analysis of the literature included 18 articles from 2007 to 2017. Of these 5 articles performed a comprehensive analysis of the national registers, 5 articles evaluated complications and reasons of failure after TAR, 6 articles made a specific outcome register analysis, one article compared TAR and ankle arthrodesis while the last one analyzed the role of TAR in patients with rheumatoid arthritis.

CONCLUSIONS

Scientific publications extracted from national joint registers for total ankle replacement provide useful but heterogeneous information on implants survivorship, implant models and risk factors. There is still a discrepancy between the data reported by designers in clinical studies and the data reported by the registries. The centralization of registers in specialized hospitals with dedicated surgeons, the use of patient reported outcomes (PROMs) in association with surgeon assessments and periodical publications can improve the development of registries and consequently of the literature in this regard.

Revision Surgery for Metal Component Failure in Total Ankle Arthroplasty

Background:

Metal component failure in total ankle arthroplasty (TAA) is difficult to treat. Traditionally, conversion to an arthrodesis has been advocated. Revision TAA surgery has become more common with availability of revision implants and refinement of bone-conserving primary implants. The goal of this study was to analyze the clinical results and patient-reported outcomes for patients undergoing revision total ankle arthroplasty.

Methods:

We retrospectively reviewed prospectively collected data on 52 patients with a mean age of 63.5 ± 9.6 years who had developed loosening or collapse of major metal components following primary TAA. These patients were compared to a case-matched control group of 52 primary TAAs performed at the host institution with a minimum of 2 years’ follow-up. Cases of isolated polyethylene exchange, infection, or extra-articular realignment procedures were excluded. The American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score, Short Form 36 (SF-36), Short Musculoskeletal Function Assessment (SMFA), and pain scores were prospectively collected. Clinical data was collected through review of the electronic medical record to identify reasons for clinical failure, where clinical failure was defined as second revision or conversion to arthrodesis or amputation.

Results:

The identified causes of failure of primary TAA were aseptic loosening of both components (42%), talar component subsidence/loosening (36%), coronal talar subluxation (12%), tibial loosening (8%), and talar malrotation (2%). Thirty-one patients (59.5%) underwent revision of all components, 20 (38.5%) just the talar and polyethylene components, and one (2%) the tibial and polyethylene components. The average time to revision was 5.5 years ± 5.4 with a follow-up of 3.1 years ± 1.5 after revision. Eleven (21.2%) revision arthroplasties required further surgery: 6 required conversion to arthrodesis and 5 required second revision TAA. Pain scores, SF-36 scores, SMFA scores, and AOFAS Hindfoot scores all improved after revision surgery but never reached the same degree of improvement seen after primary TAA.

Conclusions:

Clinical and patient-reported outcomes of revision ankle arthroplasty after metal component failure significantly improved after surgery, although the recovery time was longer. In this series, 21.2% of revision TAAs required a second revision TAA or arthrodesis surgery. Various prostheses performed similarly when used for revision surgery. Revision TAA can offer significant improvements postoperatively.

Level of Evidence:

Level III, therapeutic.

Patient-Reported Outcomes Before and After Primary and Revision Total Ankle Arthroplasty

BACKGROUND:

Studies examining the clinical outcomes of revision total ankle arthroplasty (TAA) are sparse. Revision TAA surgery has become more common with availability of revision implants and refinement of bone-conserving primary implants. In this study, patient-reported results and clinical outcomes were analyzed for a cohort of patients who underwent both primary and revision TAA at a single high-volume institution.

METHODS:

We retrospectively reviewed prospectively collected data on 29 patients with failed primary total ankle arthroplasty. Cases of isolated polyethylene exchange, infection, or extra-articular realignment procedures were excluded. Patient-reported outcome (PRO) measures and clinical results were reviewed in this longitudinal study.

RESULTS:

Fifteen patients (51.7%) underwent revision of just the talar and polyethylene components while 13 patients (44.8%) underwent revision of all components. The most common cause was talar subsidence (51.7%). The average time to revision was 3.9 years with a follow-up of 3.2 years after revision, and 3 (10.3%) revision arthroplasties required further surgery; 2 required conversion to arthrodesis and 1 required second revision TAA. Improvements in PROs were better after primary than revision TAA.

CONCLUSIONS:

Clinical and patient-reported results of revision ankle arthroplasty after metal component failure improved significantly but never reached the improvements seen after primary ankle arthroplasty. In our series, 10.3% of revision TAAs required a second revision TAA or arthrodesis surgery.

LEVELS OF EVIDENCE:

Therapeutic Level III, comparative series.

Outcome after 52 Salto Ankle Prostheses Implanted by a Single Surgeon

While ankle arthrodesis was traditionally the gold standard method of treatment for disabling end-stage ankle arthritis, total ankle replacement (TAR) has been an acceptable alternative. The satisfaction rate of patients with TAR however differs. The purpose of our study is to investigate whether implant survival and results with special emphasis on the satisfaction rate of patients treated with a TAR implanted by a single surgeon were comparable to the literature. This was a retrospective cohort study in a teaching hospital. Data was collected from 52 patients who received a total ankle replacement (TAR) between 05/2002 and 06/2014. The mean follow-up time was 4.2 years (95% CI 3.3 - 5.0). Results showed a high satisfaction rate of 94% and 94% survival of the TAR after 5 years. We conclude that TAR with the Salto prosthesis is, in our hands, a reliable solution for end-stage ankle arthritis, with results comparable to the literature.

Trends in total ankle arthroplasty and revisions in the Medicare database

Background

High failure rates and unacceptable patient outcomes have kept total ankle arthroplasty (TAA) from becoming a favorable treatment option. Modern prosthetic designs and techniques have improved outcomes and decreased revision rates. Current literature has not adequately investigated the recent trends in TAA utilization and revision rate. The purpose of this study was to determine the trends in TAA utilization and the rate of revision TAA by analyzing a comprehensive Medicare database for procedures performed between 2005 and 2012.

Methods

A retrospective review of a comprehensive Medicare database within the PearlDiver Supercomputer application (Warsaw, IN) of the index procedures TAA and revision TAA was conducted. Patients who underwent TAA and revision TAA were identified by Current Procedural Terminology (CPT)-27702, 27703, and International Classification of Disease ninth revision (ICD) codes 81.56, 81.59 respectively. The primary outcomes of this study were annual revision incidence and TAA annual utilization. Demographic data such as age, gender, and geographical location of patients were also examined.

Results

Within our study period of 2005-2012 there was a reported total of 7,181 TAAs and 1,431 revision TAAs which is a revision incidence of 19.928% amongst the Medicare population. The compound annual growth rate (CAGR) was 16.37% for TAA, 7.74% for revision TAA, and a mean 7.41% annual revision incidence. Amongst females there were 3,568 TAA and 731 revision TAA compared with 3,336 TAA and 613 revision TAA amongst males. The greatest amount of TAA and revision TAA were found in the 65-69 age group followed by the 70-74 age group. Regionally, the highest number of TAA and revision TAA were found in the South and the lowest in the Northeast.

Conclusions

Our analysis of the Medicare database shows that there is a high rate of annual growth in TAA utilization (16.37%) and revision TAA (7.74%) indicating that there is an increased demand for TAA in the Unites States. However, failed TAA can have serious consequence and revision TAA remains to have suboptimal results. This study highlights the recent trends in ankle arthroplasty and serves to increase awareness of this increasingly popular procedure.

Fixed and mobile-bearing total ankle prostheses: Effect on tibial bone strain

BACKGROUND

Total ankle replacement is associated to a high revision rate. To improve implant survival, the potential advantage of prostheses with fixed bearing compared to mobile bearing is unclear. The objective of this study was to test the hypothesis that fixed and mobile bearing prostheses are associated with different biomechanical quantities typically associated to implant failure.

METHODS

With a validated finite element model, we compared three cases: a prosthesis with a fixed bearing, a prosthesis with a mobile bearing in a centered position, and a prosthesis with mobile bearing in an eccentric position. Both prostheses were obtained from the same manufacturer. They were tested on seven tibias with maximum axial compression force during walking. We tested the hypothesis that there was a difference of bone strain, bone-implant interfacial stress, and bone support between the three cases. We also evaluated, for the three cases, the correlations between bone support, bone strain and bone-implant interfacial stress.

FINDINGS

There were no statistically significant differences between the three cases. Overall, bone support was mainly trabecular, and less effective in the posterior side. Bone strain and bone-implant interfacial stress were strongly correlated to bone support.

INTERPRETATIONS

Even if slight differences are observed between fixed and mobile bearing, it is not enough to put forward the superiority of one of these implants regarding their reaction to axial compression. When associated to the published clinical results, our study provides no argument to warn surgeons against the use of two-components fixed bearing implants.

Influence of Geometry and Depth of Resections on Bone Support for Total Ankle Replacement

BACKGROUND

Aseptic component loosening is a leading cause of revision for total ankle replacement. Different operative approaches for resecting the tibia and talus impact the bony support for the prostheses due to variations in both bone density and resection area, and may therefore impact loosening performance.

METHODS

Computed tomography data from 116 subjects were obtained, and solid models of the talus and tibia were generated. Bone density, resection area, and bony support were measured on a series of flat resections for each subject, at multiple resection depths. Similar measurements were performed using a series of subject-specific, anatomic radius-based resections ("round resections") at multiple depths. Results were compared to assess the impact of both resection type (flat vs round) and resection depth (6-16 mm for the tibia, 2-6 mm for the talus) on bony support.

RESULTS

Statistically significant decreases in bony support for both the talus and the tibia were obtained for flat resections as compared to round resections. A decrease of 8% to 19% for the tibia was seen for all resection depths; a decrease of 8% to 46% for the talus was seen, with greater decreases seen for shallower flat-cut resections.

CONCLUSION

Bony support in total ankle arthroplasty may be decreased using flat resections compared to round resections at comparable resection depths. Estimated differences are resection-level dependent and different for the distal tibia vs the proximal talus.

CLINICAL RELEVANCE

Biomechanical characteristics of total ankle replacement impacted by bony support of the prostheses, including implant stability and resistance to subsidence, may be improved with round resections as compared to flat-cut resections.

Long-term Results of Scandinavian Total Ankle Replacement

BACKGROUND

The purpose of this study was to evaluate the long-term results of the Scandinavian Total Ankle Replacement (STAR) implant in a single center.

METHODS

Between 1997 and 2002, 34 consecutive ankles were replaced with the STAR ankle prosthesis and reviewed in 2016. Patients were followed both radiologically and clinically; clinical outcomes were measured with the Kofoed ankle score and subjective measurements. The median follow-up period was 159 months (13.3 years; range, 13-202 months).

RESULTS

The implant survival rate was 93.9% (95% confidence interval [CI], 92.2%-86.7%) at 5 years, 86.7% (95% CI, 69.3%-96.2%) at 10 years, and 63.6% (95% CI, 30.8%-89.0%) at 15 years. A total of 15 ankles (44%) had been revised: 2 by fusion, 3 by further replacement, 5 by insert exchange, and 5 by bone grafting for marked osteolysis. The improvements in the Kofoed ankle score and Kofoed ankle score for pain were statistically significant at every postoperative evaluation point compared to the preoperative values (all P < .0001), and subjective patient satisfaction was high.

CONCLUSION

Our results were satisfactory and in agreement with previously reported findings of STAR implants.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Pearls and Pitfalls for a Surgeon New to Ankle Replacements

The role of the surgeon learning curve in total ankle replacement (TAR) has produced contradictory results. It is important for a new surgeon to know what clinical and radiological parameters are considered reliable and ideal. It is clear that exposure to a high-volume center will increase the reliability of a new surgeon approaching TAR. Implant choice may be influenced by surgeon training, and the debate of mobile versus fix-bearing prosthesis is still open. Anterior versus lateral approach is still an open debate, with any hypothetical advantages given by the direct vision on the center of rotation to be proven.

Midterm Outcome of the Agility Total Ankle Arthroplasty

BACKGROUND

Ankle arthritis is a debilitating condition that causes severe functional impairment. While arthrodesis has been the gold standard of surgical treatment for this condition, significant improvements in total ankle arthroplasty have made it a viable alternative. The purpose of this study was to look at the midterm follow-up of the Agility total ankle.

METHODS

A retrospective review of prospectively collected data was conducted on 127 consecutive Agility total ankles implanted between 2002 and 2009. Charts were reviewed to collect patient demographics. In addition, coronal alignment, overall arc of motion, tibiotalar component motion, syndesmotic fusion, zones of osteolysis, and subsidence were determined. A Kaplan-Meier survival and linear regression analysis were used to predict implant failure. A multivariate regression analysis was used to assess whether radiographic measures were predictive of patient satisfaction.

RESULTS

Ninety (78.2%) of 115 patients retained their primary implant, of which 105 were available for evaluation, with an average follow-up of 9.1 years. Twenty-five had their implant removed. The average score for the Foot and Ankle Ability Measure (FAAM) activities of daily living subscale was 82.4, FAAM sport subscale 55.3, postoperative visual analog scale (VAS) for pain 12.7, and Short Form-12 (SF-12) Health Survey physical component 45.8 and SF-12 mental component 56.1. Average arc of motion across the implant was 22.3 and 6.3 degrees in adjacent joints. Osteolysis most commonly occurred in zones 1 and 6. No statistical differences were found in the rate or location of subsidence. Linear regression analysis demonstrated that age at the time of surgery was predictive of failure ( P = .036). Inflammatory and atraumatic arthritis demonstrated higher likelihoods of revision. No correlation was detected between radiographic parameters and outcomes scores ( P > .05; rho >0.2). A significant reduction in mean VAS pain scores by 67.6% was maintained at an average of 8 years.

DISCUSSION

Our results were improved over the nondesigner outcomes published in the current literature. Survivorship approached 80% at 9 years, with Kaplan-Meier 14-year survival calculated at 70.4%. Patients with their original implant were functioning with a high level of satisfaction based on statistically validated outcome scores, which was independent of the radiographic appearance of their implant. Age at the time of surgery and inflammatory/atraumatic arthritis were predictive of failure.

LEVEL OF EVIDENCE

Level IV, case series.

Is There Anything to Learn from a National Joint Registry?

National joint registries (NJRs) have been established in Northern Europe for over 20 years. Since then, many other countries have begun collecting and reporting national data for total ankle arthroplasty (TAA). With relatively small numbers implanted, a large variety of available designs, and with any long-term reports dominated by designer groups, TAA is ideally placed to benefit from large national or even pooled national registries. This article reviews the existing registry-based literature with respect to what is already known. The potential positives and down sides of registry data also are highlighted.

Identifying the learning curve for total ankle replacement using a mobile bearing prosthesis

BACKGROUND

Total ankle arthroplasty remains a technically demanding surgery highly influenced by the operator experience. However, no consensus exists regarding the ideal number of cases that need to be performed before a surgeon is considered proficient. The aim of this study was to identify the learning curve of a specific replacement system with regards to intraoperative and postoperative outcomes.

METHODS

The first 31 patients undergoing total ankle arthroplasty were examined. No additional procedures were performed at the time of the TAA. Intraoperative characteristics, postoperative complications, as well as clinical and radiologic outcomes were assessed with 24-month follow-up. Learning curves, examining the relationship between surgeon experience and patient outcomes, were determined using the Moving Average Method.

RESULTS

The operatory time, and the risk of intraoperative fractures decreased with increasing surgeon experience with the learning curve stabilizing after the 14th and 24th patient, respectively. Furthermore, there appeared to be a learning curve associated with most of the important clinical and radiological outcomes. The number of patients required to stabilize the learning curve for the VAS, ROM, and AOFAS was 11, 14 and 28, respectively. Radiographically, there appeared to be a learning curve of 22 patients required to stabilize the tibio-talar ratio. There was no learning curve associated with the SF-12 PCS and MCS as well as the α-, β-, and γ-angle.

CONCLUSION

This study demonstrates that a surgical learning curve does indeed exist when performing TAA. Most of the operative variables as well as clinical and radiological outcomes stabilize after a surgeon has performed 28 cases.

Hallux valgus, ankle osteoarthrosis and adult acquired flatfoot deformity: a review of three common foot and ankle pathologies and their treatments

The pathogenesis of hallux valgus deformity is multifactorial. Conservative treatment can alleviate pain but is unable to correct the deformity. Surgical treatment must be adapted to the type and severity of the deformity. Success of surgical treatment ranges from 80% to 95%, and complication rates range from 10% to 30%.Ankle osteoarthrosis most commonly occurs as a consequence of trauma. Ankle arthrodesis and total ankle replacement are the most common surgical treatments of end stage ankle osteoarthrosis. Both types of surgery result in similar clinical improvement at midterm; however, gait analysis has demonstrated the superiority of total ankle replacement over arthrodesis. More recently, conservative surgery (extraarticular alignment osteotomies) around the ankle has gained popularity in treating early- to mid-stage ankle osteoarthrosis.Adult acquired flatfoot deformity is a consequence of posterior tibial tendon dysfunction in 80% of cases. Classification is based upon the function of the tibialis posterior tendon, the reducibility of the deformity, and the condition of the ankle joint. Conservative treatment includes orthotics and eccentric muscle training. Functional surgery is indicated for treatment in the early stages. In case of fixed deformity, corrective and stabilising surgery is performed. Cite this article: Crevoisier X, Assal M, Stanekova K. Hallux valgus, ankle osteoarthrosis and adult acquired flatfoot deformity: a review of three common foot and ankle pathologies and their treatments. EFORT Open Rev 2016;1:58-64. DOI: 10.1302/2058-5241.1.000015.

Custom-made total ankle arthroplasty for the salvage of major talar bone loss

Aims

A failed total ankle arthroplasty (TAA) is often associated with much bone loss. As an alternative to arthrodesis, the surgeon may consider a custom-made talar component to compensate for the bone loss. Our aim in this study was to assess the functional and radiological outcome after the use of such a component at mid- to long-term follow-up.

Patients and Methods

A total of 12 patients (five women and seven men, mean age 53 years; 36 to77) with a failed TAA and a large talar defect underwent a revision procedure using a custom-made talar component. The design of the custom-made components was based on CT scans and standard radiographs, when compared with the contralateral ankle. After the anterior talocalcaneal joint was fused, the talar component was introduced and fixed to the body of the calcaneum.

Results

At a mean follow-up of 6.9 years (1 to 13), 11 ankles were stable with no radiological evidence of loosening. Only one was lost to follow-up. The mean arc of movement was 21° (10° to 35°). A total of nine patients (75%) were satisfied or very satisfied with the outcome, two (17%) were satisfied but with reservations and one (8%) was not satisfied. All but one patient had an improvement in the American Orthopaedic Foot and Ankle Society hindfoot score (p = 0.01). Just one patient developed deep infection, leading to arthrodesis.

Conclusion

A custom-made talar component yielded satisfactory results with regard to function, stability and satisfaction. This should encourage the use of such components as an alternative to arthrodesis of the ankle in patients with a failed TAA. Cite this article: Bone Joint J 2017;99-B:231–6.

Analysis of Total Ankle Arthroplasty Survival in the United States Using Multiple State Databases

The aim of this study was to evaluate survivorship and risk factors for failure of total ankle arthroplasty (TAA) in the United States using large statewide, multipayer databases of inpatient discharges. TAA patients from 2005 to 2009 were identified from the Healthcare Cost and Utilization Project databases for 5 states (California, Florida, Nebraska, North Carolina, and Utah) and the New York Department of Health Statewide Planning and Research Cooperative System database. Patient demographics and clinical characteristics were extracted, and a multivariable logistic regression model was developed to assess risk factors for 90-day all-cause readmission and failure. Failure was defined as revision, arthrodesis, amputation, or implant removal. During the period of interest, 1545 patients received 1593 TAA. The coded etiology of arthritis was primary osteoarthritis (n = 854, 55.2%), posttraumatic arthritis (n = 466, 30.2%), rheumatoid arthritis (n = 129, 8.4%), and other (n = 96, 6.2%). The 5-year survival rate was 90.1%. Patients with a coded diagnosis of rheumatoid arthritis (odds ratio [OR] = 2.18; 95% confidence interval [CI] = 1.04-4.01) or who were readmitted within 90 days of TAA (OR = 3.41; 95% CI = 1.67-6.97) had significantly increased risk of failure. Risk factors for readmission were Charlson-Deyo Score ≥2 (OR = 3.05; 95% CI = 1.51-6.15) and increased length of stay during the arthroplasty (OR = 1.30; 95% CI = 1.16-1.47).

LEVELS OF EVIDENCE

Therapeutic, Level IV: Observational study.

Early Complications and Secondary Procedures in Transfibular Total Ankle Replacement

BACKGROUND

A new transfibular total ankle arthroplasty (TAA) system has not been assessed for potential early complications.

METHODS

We retrospectively assessed prospectively collected data on the initial cohort of patients undergoing TAA with this implant. We evaluated visual analog scale (VAS) pain and function, range of motion, and early radiographic outcomes.

RESULTS

Twenty consecutive TAAs (19 patients) were treated with the implant from January 2013 through June 2014. Average patient age was 63.7 (range, 41-80) years, with an average follow-up of 18 (range, 12-27) months. No fibular nonunion or implant failure was found at 12 months postoperatively. One patient had asymptomatic mild tibial lucency. Four of 20 TAAs underwent additional surgery for anterior impingement (1 ankle), deep infection and symptomatic fibular hardware (1 ankle), and symptomatic fibular hardware (2 ankles).

CONCLUSION

Of 20 ankles treated with a new transfibular arthroplasty system, no fibular nonunion, delayed union, or implant failure was noted at 12 months postoperatively. Two complications were resolved with secondary treatment, and 2 other ankles underwent secondary surgery for symptomatic fibular hardware with good outcome. The findings suggest that this total ankle system is safe and effective at short-term follow-up.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Ballooning osteolysis in 71 failed total ankle arthroplasties

Background and purpose - Aseptic loosening is a major cause of failure in total ankle arthroplasty (TAA). In contrast to other total joint replacements, large periarticular cysts (ballooning osteolysis) have frequently been observed in this context. We investigated periprosthetic tissue responses in failed TAA, and performed an element analysis of retrieved tissues in failed TAA. Patients and methods - The study cohort consisted of 71 patients undergoing revision surgery for failed TAA, all with hydroxyapatite-coated implants. In addition, 5 patients undergoing primary TAA served as a control group. Radiologically, patients were classified into those with ballooning osteolysis and those without, according to defined criteria. Histomorphometric, immunohistochemical, and elemental analysis of tissues was performed. Von Kossa staining and digital microscopy was performed on all tissue samples. Results - Patients without ballooning osteolysis showed a generally higher expression of lymphocytes, and CD3+, CD11c+, CD20+, and CD68+ cells in a perivascular distribution, compared to diffuse expression. The odds of having ballooning osteolysis was 300 times higher in patients with calcium content >0.5 mg/g in periprosthetic tissue than in patients with calcium content ≤0.5 mg/g (p < 0.001). Interpretation - There have been very few studies investigating the pathomechanisms of failed TAA and the cause-effect nature of ballooning osteolysis in this context. Our data suggest that the hydroxyapatite coating of the implant may be a contributory factor.

Epidemiology of Total Ankle Arthroplasty: Trends in New York State

The rate of total ankle arthroplasty (TAA) is increasing in the United States as its popularity and indications expand. There currently is no national joint registry available to monitor outcomes, and few studies have addressed the challenges faced with TAA. The purpose of this study was to evaluate the incidence, complications, and survival rates associated with TAA using a large statewide administrative discharge database. Individuals who underwent primary TAA from 1997 to 2010 were identified in the Statewide Planning and Research Cooperative System database from the New York State Department of Health. The age, sex, comorbidities, state of residence, primary diagnosis, and readmissions within 90 days were analyzed for patients with an ICD-9-CM procedure code of 81.56 (TAA). Failure of a TAA implant was defined as revision, tibiotalar arthrodesis, amputation, or implant removal. During the 14-year period, 420 patients underwent 444 TAAs (mean patient age of 61 years, 59% women, mean Charlson-Deyo comorbidity score of 0.45, and 86% New York State residents). The primary diagnosis was 37.4% osteoarthritis, 34.3% traumatic arthritis, and 15.5% rheumatoid arthritis. Surgery for failure was associated only with a younger age (56.5 vs 62 years, P=.005). The rate of subsequent failure procedures following TAAs performed in New York State was 13.8%. The incidence of TAAs is steadily increasing. The overall survival rate in New York State is better than rates reported in other national registries, but it is not yet comparable to those of hip and knee replacements. [Orthopedics. 2016; 39(3):170-176.].

Effect of Coronal and Sagittal Alignment on Outcome After Mobile-Bearing Total Ankle Replacement

BACKGROUND

Comparably high revision rates are reported after total ankle replacement (TAR). Therefore, further critical analysis of the influence of implant position on clinical outcome is necessary.

METHODS

We analyzed the reliability and predictive value of previously published pre- and postoperative coronal and sagittal parameters in routine ankle radiographs on the clinical outcome of 84 HINTEGRA total ankle replacements (Newdeal, Lyon, France; Integra, Plainsboro, New Jersey). Mean follow-up was 4.0 years, and 15.5% of the TARs had revision surgery.

RESULTS

Mean postoperative American Orthopaedic Foot & Ankle Society ankle-hindfoot score was 71.3; mean postoperative verbal rating scale for pain was 3.1; and mean postoperative ankle range of motion was 26.4 degrees. Most tested radiologic parameters showed moderate or high intra- and interobserver reliability. With the numbers available, no significant difference in clinical outcome for all tested radiologic parameters could be detected.

CONCLUSION

Our results indicate that mild malalignment of TAR, as assessed on routine ankle radiographs, did not affect midterm clinical outcome after TAR. Further multicenter studies with longer follow-up are needed to support our findings.

LEVEL OF EVIDENCE

Level III, comparative series.

Intraoperative and perioperative complications during revision arthroplasty for salvage of a failed total ankle arthroplasty

BACKGROUND

Revision of a failed total ankle arthroplasty (TAA) remains a challenge. Advances in total ankle implant design have renewed interest in revision TAA as an alternative to ankle arthrodesis or amputation in the management of a failed TAA. The purpose of our study was to review a series of failed Agility TAA revised to INBONE II TAA and identify reasons for revision as well as perioperative complications.

METHODS

A retrospective review of 35 cases of failed Agility TAA revised to an INBONE II TAA was performed at 1 institution. Patient demographics, indications for revision, radiographs, and complications were reviewed. The average follow-up was 9.1 months (range, 0-28 months). All revisions were performed by 1 of 2 foot and ankle surgeons familiar with both prostheses.

RESULTS

The Agility TAA lasted a mean of 6.7 years prior to revision to an INBONE II TAA. Revision TAA was indicated due to mechanical loosening, osteolysis, periprosthetic fracture, and a dislocated prosthesis. Adjunctive procedures were performed in 31 of 35 cases. There were 6 intraoperative and 5 acute postoperative complications, leading to an overall 31.4% complication rate. There was 1 patient with continued pain postoperatively who underwent a second revision of the INBONE II 20 months postoperatively.

CONCLUSION

Revision TAA was a viable treatment option for failed TAA. A high risk of perioperative complications remains, and physicians should be aware of the challenges that occur during these procedures in order to plan for them preoperatively.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Force-controlled dynamic wear testing of total ankle replacements

Currently, our knowledge of wear performance in total ankle replacements is limited. The aim of this study is to develop a scenario for force-controlled testing and wear testing of total ankle replacements. A force-controlled wear test was developed: based on cadaver measurements, the passive stabilization (ligaments and soft tissue) of the ankle joint was characterized and a restraint model for ankle stabilization was developed. Kinematics and kinetics acting at the replaced ankle joint were defined based on literature data and gait analysis. Afterwards, force-controlled wear testing was carried out on a mobile, three-component, total ankle replacement design. Wear was assessed gravimetrically and wear particles were analyzed. Wear testing resulted in a mean wear rate of 18.2±1.4mm(3)/10(6) cycles. Wear particles showed a mean size of 0.23μm with an aspect ratio of 1.61±0.96 and a roundness of 0.62±0.14. Wear testing of total ankle replacement shows that a relevant wear mass is generated with wear particles in a biologically relevant size range. The developed wear test provides a basis for future wear testing of total ankle replacements.

Strategies for Revision Total Ankle Replacement

As the frequency of primary total ankle replacement (TAR) continues to build, revision will become more commonplace. At present there are no “standard principles” associated with revision TAR. What is clear is that the current approaches are technically complex, fraught with complications and no one approach represents the only answer. Exchange of TAR metallic components to the same system standard or dedicated revision components are viable options with limited occurrence of complications. Explantation and conversion to custom-design long stemmed components has limited availability. Explantation and conversion to another TAR system is high-risk and has strong potential for complications. The use of metal reinforced polymethylmethacrylate cement augmentation of failed TAR systems and tibio-talo-calcaneal arthrodesis should be reserved for very select situations where other options are not possible. There is a real need for long-term survivorship following revision TAR and future efforts ought to be directed in this area.

Ankle salvage surgery with autologous circular pillar fibula augmentation and intramedullary hindfoot nail

Tibiotalocalcaneal arthrodesis with an intramedullary hindfoot nail is an established procedure for fusion of the ankle and subtalar joints. In cases involving ankle bone loss, such as in failed total ankle replacement, it can be difficult to salvage with sufficient bone restoration stability and a physiologic leg length and avoiding below the knee amputation. In addition to the alternatives of using a structural allograft or metal bone substitution, we describe the use of autologous ipsilateral circular pillar fibula augmentation in tibiotalocalcaneal retrograde nail arthrodesis combined with a ventral (anterior) plate in a prospective series of 6 consecutive cases with a mean follow-up duration of 26 ± 9.95 (range 12 to 34) months. The 6 patients (3 female and 3 male), with a mean age of 55 ± 13.89 (range 38 to 73) years were treated with revision surgery of the ankle (1 after talectomy, 5 [83.33%] after failed ankle replacement). The visual analog scale for pain and the American Orthopaedic Foot and Ankle Society hindfoot score were used to assess functional outcome, and radiographs and computed tomography scans were used to determine the presence of fusion. All patients improved clinically from pre- to postoperatively in regard to the mean pain visual analog scale score (from 7.5 to 2.0) and American Orthopaedic Foot and Ankle Society hindfoot score (from 29 to 65 points, of an 86-point maximum for fused joints). Radiologically, no loss in the reduction or misalignment of the hindfoot was detected, and all cases fused solid. One patient (16.67%) required hardware removal. The fixation construct provided good clinical and radiologic outcomes, and we recommend it as an alternative to structural allografts or metallic bone grafts for revision ankle surgery with severe bone loss.

Assessment of a three-grade classification of complications in total ankle replacement

BACKGROUND

Prompted by the success of hip and knee arthroplasty, total ankle replacement (TAR) has become increasingly popular as a treatment for end stage arthritis of the ankle. A 3-grade classification of complications to assist in prediction of early implant failure has been proposed. We have compared the experience of a tertiary referral center in the United Kingdom to the proposed system.

METHODS

A retrospective review of the Sheffield Foot and Ankle Unit TAR database was performed from 1995 to 2010. All complications were recorded and categorized using Glazebrook et al's proposed system of increasing severity. Low-grade complications including postoperative bone fracture, intraoperative bone fracture, and wound healing problems rarely lead to revision. Medium-grade complications, technical error and subsidence, lead to failure <50% of the time. High-grade complications--deep infection, aseptic loosening, and implant failure--lead to revision >50% of the time. In our center, 217 TAR were implanted in 198 patients with a minimum follow-up of 30 months.

RESULTS

The complication rate was 23%, with a revision rate of 17%. All complications recorded in our study except intraoperative bone fracture and wound healing had a failure rate of at least 50%.

CONCLUSION

Unfortunately most complications associated with TAR have a significant impact on the life span of a TAR. Glazebrook et al's proposed 3-tier system did not reliably reflect our experience. Hence, we would categorize complications as either high or low risk for early failure of TAR.

LEVEL OF EVIDENCE

Level IV, case series.

Intermediate-term results of total ankle replacement and ankle arthrodesis: a COFAS multicenter study

BACKGROUND

Surgical treatments for end-stage ankle arthritis include total ankle replacement and ankle arthrodesis. Although arthrodesis is a reliable procedure, ankle replacement is often preferred by patients. This prospective study evaluated intermediate-term outcomes of ankle replacement and arthrodesis in a large cohort at multiple centers, with variability in ankle arthritis type, prosthesis type, surgeon, and surgical technique. We hypothesized that patient-reported clinical outcomes would be similar for both procedures.

METHODS

Patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstruction Database were treated with total ankle replacement (involving Agility, STAR, Mobility, or HINTEGRA prostheses) or ankle arthrodesis by six subspecialty-trained orthopaedic surgeons at four centers between 2001 and 2007. Data collection included demographics, comorbidities, and the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36) scores. The preoperative and latest follow-up scores for patients with at least four years of follow-up were analyzed. Sensitivity analyses excluded ankles that had undergone revision. A linear mixed-effects regression model compared scores between the groups, adjusting for age, sex, side, smoking status, body mass index, inflammatory arthritis diagnosis, baseline score, and surgeon.

RESULTS

Of the 388 ankles (281 in the ankle replacement group and 107 in the arthrodesis group), 321 (83%; 232 ankle replacements and eighty-nine arthrodeses) were reviewed at a mean follow-up of 5.5 ± 1.2 years. Patients treated with arthrodesis were younger, more likely to be diabetic, less likely to have inflammatory arthritis, and more likely to be smokers. Seven (7%) of the arthrodeses and forty-eight (17%) of the ankle replacements underwent revision. The major complications rate was 7% for arthrodesis and 19% for ankle replacement. The AOS total, pain, and disability scores and SF-36 physical component summary score improved between the preoperative and final follow-up time points in both groups. The mean AOS total score improved from 53.4 points preoperatively to 33.6 points at the time of follow-up in the arthrodesis group and from 51.9 to 26.4 points in the ankle replacement group. Differences in AOS and SF-36 scores between the arthrodesis and ankle replacement groups at follow-up were minimal after adjustment for baseline characteristics and surgeon.

CONCLUSIONS

Intermediate-term clinical outcomes of total ankle replacement and ankle arthrodesis were comparable in a diverse cohort in which treatment was tailored to patient presentation; rates of reoperation and major complications were higher after ankle replacement.

Registry data trends of total ankle replacement use

Joint arthroplasty registry data are meaningful when evaluating the outcomes of total joint replacement, because they provide unbiased objective information regarding survivorship and incidence of use. Critical evaluation of the registry data information will benefit the surgeon, patient, and industry. However, the implementation and acceptance of registry data for total ankle replacement has lagged behind that of hip and knee implant arthroplasty. Currently, several countries have national joint arthroplasty registries, with only some procuring information for total ankle replacement. We performed an electronic search to identify publications and worldwide registry databanks with pertinent information specific to total ankle replacement to determine the type of prostheses used and usage trends over time. We identified worldwide registry data from 33 countries, with details pertinent to total ankle replacement identified in only 6 countries. The obtained information was arbitrarily stratified into 3 distinct periods: 2000 to 2006, 2007 to 2010, and 2011. Within these study periods, the data from 13 total ankle replacement systems involving 3,980 ankles were identified. The vast majority (97%) of the reported ankle replacements were 3-component, mobile-bearing, uncemented prostheses. Three usage trends were identified: initial robust embracement followed by abrupt disuse, minimal use, and initial embracement followed by sustained growth in implantation. Before the widespread acceptance of new total ankle replacements, the United States should scrutinize and learn from the international registry data and develop its own national joint registry that would include total ankle replacement. Caution against the adoption of newly released prostheses, especially those without readily available revision components, is recommended.

[Revision rates in journal publications on joint prostheses with noticeably high failure rates in register data sets]

BACKGROUND AND AIM OF STUDY

The value of outcome quality data from clinical studies is an issue of controversial debate particularly in the context of adverse events. The aim of this study is to present and evaluate the data available from clinical studies for products that show inferior outcome in registers and to assess the possibility to draw valid conclusions from these data. STUDY DESIGN AND ANALYTICAL METHODS: Based on a structured literature research, a comparative analysis was made of the revision rates of 12 products showing significantly inferior average results in registers. The primary outcome parameter was the revision rate for any reason calculated using a standardized methodology and the parameter of revisions per 100 observed component years.

RESULTS

For 5 out of 12 products not a single comparable study was available and relatively few data were available for the remaining products. A conventional meta-analysis revealed that only three products showed results that were comparable with those from registers. For 75% of products good results were published. There was not a single case where it would have been possible to identify or isolate the problems that had led to the underperformance observed on the basis of clinical studies alone.

DISCUSSION

Clinical sample-based studies are not a suitable and reliable means to recognize potential product or handling problems and avoid risks for patients and physicians. In this respect registers can provide an essential contribution.

Agility to INBONE: anterior and posterior approaches to the difficult revision total ankle replacement

Total ankle replacement is now acknowledged as a viable alternative to ankle arthrodesis for end-stage ankle arthritis. The authors present a series of 14 patients who were converted from the Agility total ankle replacement to an INBONE total ankle replacement. This report is unique in that anterior and posterior approaches are discussed and detailed. Although the authors present successful conversion of the Agility total ankle replacement to an INBONE total ankle replacement, the difficulty of this procedure is demonstrated by the high complication rate and 2 early failures.

Salvage of a failed DePuy Alvine Total Ankle Prosthesis with Agility LP custom stemmed tibia and talar components

This article presents a procedure whereby a second-phase design DePuy Alvine Total Ankle Prosthesis underwent revision to an Agility LP custom-designed stemmed tibial and talar component total ankle replacement system. The rationale for this procedure, the process of developing the custom components, the operative sequence of events, and recovery course are presented in detail. Causes for concern regarding subsequent revision, should this be required, are raised.

Mobile- and fixed-bearing total ankle prostheses: is there really a difference?

Approximately 1% of the world's adult population is affected by ankle osteoarthritis (OA). Therapeutic options include conservative and surgical measures. Because of substantial progress in total ankle replacement, ankle fusion is no longer the "gold standard" therapy for end-stage ankle OA. Various ankle prostheses have been designed and are currently available. This article reviews the in vitro studies addressing the biomechanics and kinematics of the replaced ankle. Furthermore, a systematic literature review was conducted to assess possible differences in clinical outcomes, including prosthesis survivorship and postoperative range of motion between mobile- and fixed-bearing total ankle prostheses.