Better implant survival with modern ankle prosthetic designs: 1,226 total ankle prostheses followed for up to 20 years in the Swedish Ankle Registry

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

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

Clinical Outcomes and Registry Data in Total Ankle Arthroplasty

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

Outcomes of Total Ankle Replacement with Preoperative Varus Deformity

Historically, coronal plane deformities of greater than 10° to 15° have been deemed contraindications for total ankle replacement (TAR). However, recent studies show satisfactory results in TAR with severe preoperative varus deformity. When correctly applying ancillary procedures, preoperative varus deformity can be structurally corrected, resulting in similar clinical scores to those obtained with "regular TAR." However, complications and revisions appear to increase with increasing deformity. Unfortunately, results of TAR in varus ankles consist of heterogeneous data (eg, with regards to prosthetic brands, bearing-types, duration of follow-up, and ancillary procedures) precluding strict conclusions. This could be solved by an international consensus group.

Total ankle replacement versus ankle fusion for end-stage ankle arthritis: A meta-analysis

PURPOSE

This study aims to systematically review the efficacy and safety of total ankle replacement (TAR) and ankle fusion (AF) as treatment options for end-stage ankle arthritis.

METHODS

A comprehensive literature search was conducted on data from multiple databases, including PubMed, The Cochrane Library, Construction and Building Materials, Embase, Web of Science, and Scopus for RCTs and prospective cohort studies comparing TAR and AF in patients with end-stage ankle arthritis from inception up to June, 2023. Our primary outcomes of interest included patients' clinical function scores and complications. We employed Review Manager 5.4 and Stata/MP 14.0 software for the meta-analysis.

RESULTS

Our analysis incorporated 13 comparative studies, including 11 prospective studies, one pilot RCT, and one RCT. The pooled results revealed no significant difference in postoperative Short Form-36 scores between the TAR and AF groups (MD = -1.19, 95% CI: -3.89 to 1.50, p = .39). However, the postoperative Foot and Ankle Ability Measure scores in the AF group were significantly higher than in the TAR group (MD = 8.30, 95% CI: 1.01-15.60, p = .03). There was no significant difference in postoperative complication rates between the TAR and AF groups (RR = 0.95, 95% CI: 0.59 to 1.54, p = .85).

CONCLUSION

Currently available evidence suggests no significant disparity in postoperative outcomes between TAR and AF. In the short term, TAR demonstrates better clinical scores than AF and lower complication rates. Conversely, in the long term, AF exhibits superior clinical scores and lower complication rates, although this difference is not statistically significant.

STAR® total ankle replacements with BONIT® coating: A prospective 2-17 year follow-up study of 474 ankles from a single center

BACKGROUND

Different coatings of the metal implants of STAR prostheses have been used since 1999. In Europe metal implants with a double calcium-phosphate coating (BONIT) on a titanium sprayed surface have been available since 1999.

METHODS

We present a 2-17 year follow-up of a consecutive series from a single center with 474 STAR ankle replacements where the BONIT type of coating has been used.

RESULTS

55 prostheses (12%) have been revised, the majority of them due to fracture of the mobile bearing. 22 prostheses (5%) have been converted to an arthrodesis. Analysis of survival of the specific components showed an estimated 10-year survival rate of the tibia component, talus component and polyethylene mobile bearing of 99%, 98% and 84%, respectively. The corresponding estimated 15-year survival was 98%, 98% and 74%, respectively.

CONCLUSION

This study showed an extraordinary high survival rate of the metal implants.

LEVEL OF EVIDENCE

Level III, prospective cohort series.

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

BACKGROUND

Total ankle arthroplasty (TAA) has higher complication and failure rates compared to other surgical joint replacement procedures despite technological advances. This study aimed to find the long-term survivability of the TAA procedure and identify the patient risk factors for failure with one of the largest cohorts of patients in the literature.

METHODS

This retrospective cohort study involving cases between 2007 and 2018 analyzed patients who received an index primary TAA procedure in Korea. A total of 5619 cases were included in the final analysis. The TAA failure was defined as either a case with revision arthroplasty or a case with TAA implant removal and arthrodesis performed after primary TAA.

RESULTS

During the study period, the 5-year survival rate was 95.4% (95% CI, 94.7-96.1%), and the 10-year survival rate was 91.1% (95% CI, 89.1-93.1%). A younger age (<55 years, adjusted hazard ratio [AHR], 1.725; 55-64 years, AHR, 1.812; p < 0.001 for both), chronic pulmonary disease (AHR, 1.476; p = 0.013), diabetes (AHR, 1.443; p = 0.014), and alcohol abuse (AHR, 1.524; p = 0.032) showed a significantly high odds ratio for primary TAA failure in Cox regression analysis.

CONCLUSION

The 10-year TAA survivorship rate was 91.1%. A younger age, chronic pulmonary disease, diabetes, and heavy alcohol consumption are risk factors for TAA.

Poor survivorship of total ankle replacements. 1368 cases from the period 1994-2021 in the Norwegian arthroplasty register

BACKGROUND AND PURPOSE

The aim of the study was to present the performance of total ankle replacements (TAR) in a national register.

METHODS

All surgeons in the country report to the Norwegian Arthroplasty Register. The completeness of primary TARs in NAR was 79-90% in the years 2017-2020. Cox regression analyses and the Kaplan-Meier method were used to study implant survival and revision risk.

RESULTS

1368 primary TAR´s were implanted in 1266 patients during the period 1994-2021. The last few years saw a marked decrease in the incidence of TARs. The overall survival at 5 years was 81.1% (80.9-81.3) and 69.3% (66.4-72.2) at 10 years. Higher age was strongly associated with better survival. Current prosthesis designs had a better survival than earlier designs ((HRR 0.7, 95% CI 0.6-0.9) CONCLUSION: Revision rates were high in our registry, but current implants had better survival. Younger age increased the risk of revision.

LEVEL OF EVIDENCE

Level II: prospective cohort study.

[Total arthroplasty of the ankle joint : Limitations and potentials]

Total arthroplasty of the ankle joint (TAA) has become an established treatment option for patients with advanced osteoarthritis of the ankle joint. A crucial factor for good long-term clinical results and standing times is careful patient selection, taking the indications, contraindications, and defined prognostic factors into account. Despite modern prosthetic designs, TAA remains a complex surgical procedure that requires precise surgical techniques in a specialized center. Various limitations exist, such as the implantation technique and experience of the surgeon and perioperative complications due to concomitant medications. Current research focuses on the optimization of implant designs, development of personalized surgical techniques, improvement of the long-term performance and minimization of perioperative complications. Future developments, such as the introduction of robot-assisted surgical systems and the integration of biological procedures are also discussed as technological perspectives.

The ceramic coated implant (CCI). Evolution total ankle replacements: a retrospective analysis of 40 ankles with 8 years follow-up

Diminutive data is available on the outcome of several previously used total ankle replacement implants. The purpose of this study was to investigate the medium-term functional and radiological outcome and implant survival of the CCI Evolution implant. Consecutive series of 40 ankles operated in our hospital with primary TAR using the CCI Evolution implant in 2010-2013 were available for follow-up. The prospective clinical and radiographic data including the Kofoed score, subjective satisfaction and standard radiographs were collected preoperatively and at fixed time-points postoperatively. A CT was obtained in cases where osteolysis or loosening were suspected. The improvement of the Kofoed score and subjective satisfaction were statistically significant (p<0.0001). The implant survival was 97% (95% confidence interval (CI) 81%-100 %) at 5 years, and 81 % (95% confidence interval (CI) 60 %-92%) at 8 years. There were altogether 25 (64%) complications. Overall revision rate was 28% and failure rate 13%. The CCI implant outcome was not acceptable. The malposition of prosthetic components, subsidence, and peri-implant osteolysis were recorded often. Although the patient reported outcome measures improved, mostly due to positive changes in pain severity, overall revision and failure rates were high and comparable with previous findings of the CCI implant.

Supramalleolar osteotomies for ankle arthritis: a systematic review

INTRODUCTION

We investigated the mid-term outcomes of supramalleolar osteotomies regarding "survivorship" [before ankle arthrodesis (AA) or total ankle replacement (TAR)], complication rate and adjuvant procedures required.

MATERIAL AND METHODS

PubMed, Cochrane and Trip Medical Database were searched from January 01, 2000. Studies reporting on SMOs for ankle arthritis, in minimum of 20 patients aged 17 or older, followed for a minimum of two years, were included. Quality assessment was performed with the Modified Coleman Methodology Score (MCMS). A subgroup analysis of varus/valgus ankles was performed.

RESULTS

Sixteen studies met the inclusion criteria, with 866 SMOs in 851 patients. Mean age of patients was 53.6 (range 17-79) years, and mean follow-up was 49.1 (range 8-168) months. Of the arthritic ankles (646 ankles), 11.1% were classified as Takakura stage I, 24.0% as stage II, 59.9% as stage III and 5.0% as stage IV. The overall MCMS was 55.2 ± 9.6 (fair). Eleven studies (657 SMOs) reported on "survivorship" of SMO, before arthrodesis (2.7%), or total ankle replacement (TAR) (5.8%) was required. Patients required AA after an average of 44.6 (range 7-156) months, and TAR after 36.71 (range 7-152) months. Hardware removal was required in 1.9% and revision in 4.4% of 777 SMOs. Mean AOFAS score was 51.8 preoperatively, improving to 79.1 postoperatively. Mean VAS was 6.5 preoperatively and improved to 2.1 postoperatively. Complications were reported in 5.7% (44 out of 777 SMOs). Soft tissue procedures were performed in 41.0% (310 out of 756 SMOs), whereas concomitant osseous procedures were performed in 59.0% (446 out of 756 SMOs). SMOs performed for valgus ankles failed in 11.1% of patients, vs 5.6% in varus ankles (p < 0.05), with disparity between the different studies.

CONCLUSIONS

SMOs combined with adjuvant, osseous and soft tissue, procedures, were performed mostly for arthritic ankles of stage II and III, according to the Takakura classification and offered functional improvement with low complication rate. Approximately, 10% of SMOs failed and patients required AA or TAR, after an average of just over 4 years (50.5 months) after the index surgery. It is debatable whether varus and valgus ankles treated with SMO reveal different success rates.

Metal debris release is commonly seen from explanted total ankle replacements

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

Alignment of CCI total ankle replacements in relation to midterm functional outcome and complication incidence

BACKGROUND

Total ankle arthroplasty is increasingly used as a treatment for end stage ankle arthropathy. The aim of this study was to report the mid-term clinical function and survival results of Ceramic Coated Implant (CCI) ankle replacements and assess the association between the alignment of the CCI total ankle replacements and early functional outcome and complication incidence.

METHODS

Data of 61 patients, who received 65 CCI implants between 2010 and 2016, were obtained from a prospectively documented database. Mean follow-up time was 85.2 months (range 27-99 months). Clinical function was assessed with AOFAS questionnaire and passive range of motion (ROM). Survival analysis and elaborate radiographic analysis was performed. Furthermore, complications and reoperations were recorded for all patients.

RESULTS

Progression in ROM was most seen in the first 10 months from 21.8 degrees of passive range of motion preoperative to 27.6 degrees postoperative (p < 0.001), while the mean AOFAS gradually increased during follow-up postoperative from a mean of 40.9 points preoperative to an average of 82.5 but shows a small decline towards the end of follow-up (p < 0.001). During follow-up we recorded 8 failures (12.3%) resulting in a Kaplan-Meier survival analysis of 87.7% with a median follow-up of 85.2 months.

CONCLUSION

We observed excellent clinical results and survival after TAA with the CCI implant with only a low mid-term complication rate.

LEVEL OF EVIDENCE

Level III, prospective cohort study.

Intermediate to long-term clinical outcomes and survival analysis of the Salto Mobile Bearing total ankle prothesis

INTRODUCTION

Osteoarthritis of the ankle is a major burden to affected patients. While tibio-talar arthrodesis has been the gold-standard regarding the treatment of osteoarthritis of the ankle joint for many years, at present total ankle arthroplasty (TAA) provides appealing clinical outcomes and is continually gaining popularity. The aim of this study was to evaluate the intermediate- to long-term clinical outcome including the survival rate of Salto Mobile Bearing TAA (Tonier SA, Saint Ismier, France).

MATERIAL AND METHODS

In this retrospective study intermediate- to long-term outcomes measures [Ankle Range of Motion (ROM), American Orthopaedic Foot and Ankle Score (AOFAS score) and survival rate] of 171 consecutive TAA were analysed and compared before and after surgery. Revision was defined as secondary surgery with prothesis component removal, while reoperation was defined as a non-revisional secondary surgery involving the ankle.

RESULTS

At a mean follow-up (FU) period of 7.2 ± 2.7 years (range 2.0 to 14.1 years) there was a significant improvement in ankle ROM (total ROM improved from 25.0° ± 15.0° to 28.7° ± 11.3°, p = 0.015; plantarflexion improved from 18.4° ± 11.7° to 20.6° ± 8.2°, p = 0.044; dorsiflexion improved from 6.6° ± 5.7° to 8.1° ± 4.9°, p = 0.011). AOFAS score increased significantly by 41 ± 15 points after surgery (43.3 ± 11.1 before and 84.3 ± 12.0 after surgery, p < 0.001). Overall survival rate within the FU was 81.3% (95% CI 75.3% to 87.3%) with any secondary surgery, 89.9% (95% CI 84.1% to 93.6%) with revision and 93.6% (95% CI 89.8% to 97.3%) with reoperation as endpoint.

CONCLUSION

This study endorses the previously reported appealing intermediate- to long-term outcomes of the Salto Mobile Bearing TAA. There was a significant increase in ROM and AOFAS score as well as decent implant survival at final FU.

Risk factors for total ankle arthroplasty failure: A Dutch Arthroplasty Register study

BACKGROUND

Studies concerning total ankle arthroplasty could be influenced by several forms of bias. Independent national arthroplasty registries represent objective data on survival and patient reported outcomes. The aim of this study was to determine survival and identify risk factors for early failure in a nationwide series of total ankle arthroplasties from the Dutch Arthroplasty Register (LROI).

PATIENTS AND METHODS

Data of 810 patients, who received 836 total ankle arthroplasties between 2014 and 2020 were obtained from the Dutch Arthroplasty Register (LROI) with a median follow-up of 38 months (range 1-84 months). Survival was expressed in Kaplan-Meier analysis and associated hazard ratios for implant failure were determined. Implant failure was defined as the need for revision surgery for any reason or (pan)arthrodesis.

RESULTS

During follow-up, we recorded 39 failures (4.7%) resulting in a implant survival of 95.3% with a median follow-up of 38 months (range 1-84 months). Medial malleolus osteotomy (HR = 2.27), previous surgery (HR = 1.83), previous osteotomy (HR = 2.82) and previous ligament reconstruction (HR = 2.83) all showed potentially clinically meaningful associations with a higher incidence of implant failure, yet only previous OCD treatment (HR = 6.21), BMI (HR = 1.09) and age (HR = 0.71) were statistically significant.

INTERPRETATION

Excellent short-term survival (95.3%) with a median follow-up of 38 months was reported for TAA patients from the Dutch Arthroplasty Register. Patients with a lower age, a higher BMI or who had a prior surgical OCD treatment before TAA surgery appear to have a higher risk for revision after short-term clinical follow-up. Thorough patient selection with emphasis on risk factors associated with early implant failure might be essential to improve TAA survivorship.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

IV.

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

BACKGROUND AND PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

INTERPRETATION

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

Survival of primary ankle replacements: data from global joint registries

BACKGROUND

Ankle arthroplasty, commonly known as ankle replacement, is a surgical procedure for treating end-stage ankle osteoarthritis. Whilst evidence shows good clinical results after surgery, little is known of the long-term survival of ankle replacements and the need for ankle revision. Using more recent implant data and long-term data, there is now opportunity to examine at a population-level the survival rate for ankle implants, to examine between-country differences in ankle revision surgery, and to compare temporal trends in revision rates between countries.

METHODS

Four national joint registries from Australia, New Zealand, Norway and Sweden provided the necessary data on revision outcome following primary ankle replacement, for various periods of observation - the earliest starting in 1993 up to the end of 2019. Data were either acquired from published, online annual reports or were provided from direct contact with the joint registries. The key information extracted were Kaplan-Meier estimates to plot survival probability curves following primary ankle replacement.

RESULTS

The survival rates varied between countries. At 2 years, across all registries, survival rates all exceeded 0.9 (range 0.91 to 0.97). The variation widened at 5 years (range 0.80 to 0.91), at 10 years (range 0.66 to 0.84) and further at 15-years follow-up (0.56 to 0.78). At each time point, implant survival was greater in Australia and New Zealand with lower rates in Sweden and Norway.

CONCLUSIONS

We observed variation in primary ankle replacement survival rates across these national registries, although even after 5 years, these population derived data show an 80% revision free survival. These data raise a number of hypotheses concerning the reasons for between-country differences in revision-free survival which will require access to primary data for analysis.

Survivorship of 4,748 Contemporary Total Ankle Replacements from the French Discharge Records Database

BACKGROUND

Studies of survivorship of primary total ankle replacements (TARs) beyond 5 years have shown varying results among early and modern designs. National cohorts give valuable insights about TAR outcomes, revision risk factors, and specific designs. The purpose of this study was to investigate implant survivorship and risk factors for revision of contemporary TARs using our national database.

METHODS

This observational study included patients identified in the national PMSI (Programme médicalisé des systèmes d'information) database as having undergone TAR from 2010 to 2019. Demographics, discharge data, concomitant procedures, and type of implant were extracted. Kaplan-Meier estimations were performed to determine time to revision using metal component revision for implant failure and revision for deep infection as end points. Weighted Cox models were used for risk factor analysis, including risks of early revision (within the first 2 years). The adjusted hazard ratios (HRadj) were reported with 95% confidence intervals.

RESULTS

A cohort of 4,748 patients was extracted. The mean age at surgery was 63 years; 43% of the patients were female. The mean follow-up was 5 years (range, 1 to 10 years). Revisions were noted in 817 cases (17%), including 734 with metal component revision and 83 with revision due to deep infection. The 1-year, 2-year, 5-year, and 10-year survivorship free of metal component revision was 95%, 90%, 84%, and 78%, respectively. Younger age, implants derived from second-generation designs, and an institutional volume of ≤10 TARs per year were found to be independent predictors of revision for any cause. In addition to the above factors (except for implant generation), male sex and concomitant osteotomies and/or fusion were found to be significant predictors for any early revision.

CONCLUSIONS

The 10-year survivorship free of metal component revision after TAR was 78%, which was consistent with other national registries. Revisions were associated with young age, associated arthritis or deformities requiring concomitant fusion or osteotomy, and implants derived from second-generation designs. Institutions where >10 procedures were performed per year were associated with better TAR survivorship.

LEVEL OF EVIDENCE

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

Transfibular total ankle arthroplasty : a new reliable procedure at five-year follow-up

AIMS

This study reports updates the previously published two-year clinical, functional, and radiological results of a group of patients who underwent transfibular total ankle arthroplasty (TAA), with follow-up extended to a minimum of five years.

METHODS

We prospectively evaluated 89 patients who underwent transfibular TAA for end-stage osteoarthritis. Patients' clinical and radiological examinations were collected pre- and postoperatively at six months and then annually for up to five years of follow-up. Three patients were lost at the final follow-up with a total of 86 patients at the final follow-up.

RESULTS

A total of 86 patients were evaluated at a mean follow-up of 65.4 months (60 to 90). At five-year follow-up, statistically significant improvements (p < 0.001) were found in the mean American Orthopaedic Foot & Ankle Society Ankle Hindfoot Score (from 33.8 (SD 14.3) to 86.1 (SD 8.8)), visual analogue scale for pain (from 8.5 (SD 1.7) to 1.5 (SD 1.2)), Short Form-12 Physical and Mental Component Scores (from 29.9 (SD 6.7) and 43.3 (SD 8.6) to 47.3 (SD 7.5) and 52.2 (SD 8.0), respectively), and mean ankle dorsiflexion and plantarflexion (from 6.2° (SD 5.5°) and 9.6° (SD 5.8°) to 23.9° (SD 7.7°) and 16.9° (SD 7.2°), respectively). Radiologically, the implants maintained neutral alignment without subsidence. Tibial or talar radiolucency was found in eight patients, but none of these patients was symptomatic. At five-year follow up, 97.7% of implants (95% confidence interval 91.2 to 99.4) were free from revision or removal with 84 implants at risk. We recorded two cases (2.3%) of failure for septic loosening.

CONCLUSION

Transfibular TAA is safe and effective with a high survival rate at mid-term follow-up and satisfactory clinical and radiological results. Further studies are required to determine the long-term performance of these implants. Cite this article: Bone Joint J 2022;104-B(4):472-478.

[Salvage options following failed total ankle arthroplasty]

The number of patients with osteoarthritis of the ankle, which are treated by arthroplasty, has continuously increased in recent years. The survival time of these implants is far below the results following hip and knee arthroplasty. In some cases a failure rate of approximately 1% per year or a survival rate of 70% after 10 years has been reported. The most frequent reasons for revision of an ankle prosthesis are aseptic loosening, technical implantation errors and persisting pain. For the revision of an ankle prosthesis there are basically two treatment options. For a long time, ankle arthrodesis was considered the gold standard after a failed prosthesis. In recent years, there has been an increasing trend towards re-implantation of an ankle prosthesis, as this preserves the functionality and mobility of the ankle joint as far as possible. Depending on the reason for failure and the size of the bony defect, a decision must be made regarding a one-stage and a two-stage procedure with bone augmentation. This article presents the advantages and disadvantages of arthrodesis and revision arthroplasty after failed primary ankle arthroplasty and highlights the special features of surgery.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

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

Evaluating and Managing the Painful Total Ankle Replacement

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

Finite-element analysis of the influence of tibial implant fixation design of total ankle replacement on bone-implant interfacial biomechanical performance

PURPOSE

Implant loosening in tibia after primary total ankle replacement (TAR) is one of the common postoperative problems in TAR. Innovations in implant structure design may ideally reduce micromotion at the bone-implant interface and enhance the bone-implant fixation and initial stability, thus eventually prevents long-term implant loosening. This study aimed to investigate (1) biomechanical characteristics at the bone-implant interface and (2) the influence of design features, such as radius, height, and length.

METHODS

A total of 101 finite-element models were created based on four commercially available implants. The models predicted micromotion at the bone-implant interface, and we investigated the impact of structural parameters, such as radius, length, and height.

RESULTS

Our results suggested that stem-type implants generally required the highest volume of bone resection before implantation, while peg-type implants required the lowest. Compared with central fixation features (stem and keel), peripherally distributed geometries (bar and peg) were associated with lower initial micromotions. The initial stability of all types of implant design can be optimized by decreasing fixation size, such as reducing the radius of the bars and pegs and lowering the height.

CONCLUSION

Peg-type tibial implant design may be a promising fixation method, which is required with a minimum bone resection volume and yielded minimum micromotion under an extreme axial loading scenario. Present models can serve as a useful platform to build upon to help physicians or engineers when making incremental improvements related to implant design.

Effectiveness of ankle fusion in patients with hemophilia, advanced ankle degeneration, and unbearable pain for whom nonsurgical and surgical treatments have been ineffective

Introduction: In underdeveloped countries, patients with hemophilia often experience repetitive ankle joint hemorrhages due to a shortage of coagulation factors (factor VIII [FVIII] and factor IX [FIX] for hemophilia A and B, respectively).Areas covered: This is a narrative literature review in which we searched the Cochrane Library and PubMed for articles related to ankle arthrodesis in patients with hemophilia. The searches covered the period from the databases´ inception to 28 February 2021. In the event of unsuccessful hematologic prophylaxis and conservative measures (e.g. analgesics, cyclooxygenase-2 inhibitors, taping, intra-articular injections of hyaluronic acid and corticosteroids, physical and rehabilitation medicine, orthoses, radiosynovectomy, and joint-preserving surgery (e.g. removal of the distal tibia by open surgery or by arthroscopic surgery, joint debridement by arthroscopic surgery), the classical surgical solution is ankle arthrodesis, which does not preserve the ankle joint.Expert opinion: Ankle pain is reduced after ankle arthrodesis (75% of patients experience no pain). Approximately 5% of patients require reoperation due to lack of fusion, and deep infection occurs in 2.5%. After tibiotalar fusion, a self-reported activity scale shows that approximately 12% of patients improve, 9% worsen, and 79% show no improvement. The results of ankle arthrodesis therefore appear to be poor.Therefore, although 75% of the patients stopped having ankle pain after arthrodesis, according to a self-reported activity scale 88% of them did not improve or worsened.