Total ankle replacement

Short-Term Outcomes of Primary Total Ankle Arthroplasty in Octogenarians: A National Database Analysis

BACKGROUND

Total ankle arthroplasty (TAA) is an increasingly popular option for end-stage ankle arthritis. Americans over the age of 80 years grew to 16.7 million in 2010, but there are scarce data assessing the outcomes of octogenarians undergoing TAA. This study evaluated (1) perioperative factors, (2) 30-day postoperative complications compared to a nonoctogenarian cohort, and (3) independent risk factors for adverse outcomes.

METHODS

A national database registry was queried for patients who had undergone primary TAA. This yielded 1113 patients, under (n = 1059) and over (n = 54) age 80 years. Demographics and perioperative data were compared using Fisher's exact, χ², and independent-samples t tests. Logistic and Poisson regressions were used to calculate odds ratio (OR) of complications and independent risk factors.

RESULTS

The octogenarian cohort had longer in-hospital length of stay (1.9 vs 2.5 days, P < .0001). Octogenarians were not significantly more likely to develop any complication (OR = 1.32; 95% confidence interval = 0.29-6.04; P = .722), or increased number of complications (OR = 1.18; 95% CI = 0.27-5.18; P = .820). Octogenarians had significantly increased risk of being discharged to rehab/skilled nursing (OR = 6.60; 95% CI = 2.16-20.15; P < .001) instead of home.

CONCLUSION

Although the elderly population may carry inherent risk factors, octogenarians do not present an increased risk of short-term complications following TAA.

LEVELS OF EVIDENCE

Therapeutic, Level III: Retrospective cohort study.

The Most-Cited Ankle Arthroplasty Implant Articles

Background:

Citation analysis is a useful way of evaluating the impact, importance, and merit of articles within a medical specialty. Our study identified and analyzed the most-cited articles on ankle arthroplasty implants to evaluate their importance in the field of ankle arthroplasty research.

Methods:

Using the keywords “ankle arthroplasty” and “ankle replacement” and the search period 1970-2021, we found 3728 articles on ankle arthroplasty implants in the Scopus, Web of Science, and MEDLINE/PubMed databases. We included original articles, reviews, clinical trials, and case reports in the study. We retrieved the 50 most-cited articles published during the time frame and then screened them for studies of specific ankle arthroplasty implants and their postoperative outcomes. We also recorded and analyzed the articles’ subjects, authorship, journals, countries of origin, and years of publication.

Results:

The 50 most-cited articles were published between 1983 and 2014, with the majority (33) published between 2000 and 2010. They generated 9012 citations in the literature. The most-cited study accounted for 497 citations; the mean number of citations per article was 180.24 ± 76.24. Twenty-three (46%) of the articles addressed postoperative outcomes following a specific type of arthroplasty implant. Arthroplasty implant studies accounted for 4726 citations, or 52.4% of the citations of the 50 articles. The most frequently studied arthroplasty implant was STAR (15), followed by Agility (7), Buechel Pappas (5), and Salto (4). STAR accounted for 3311 citations, or 37% of the total citations of the 50 articles.

Conclusion:

Ankle arthroplasty research has made great progress in the past 2 decades, particularly in the area of postoperative outcomes of specific ankle implants, but continued research and publication on additional arthroplasty implants should become a priority.

Level of Evidence:

Level V, Review Article.

Estimating tissue-level properties of porcine talar subchondral bone

Tissue-level properties of bone play an important role when characterising apparent-level bone biomechanical behaviour and yet little is known about its effect at this hierarchical level. In combination with trabecular morphological data these properties can be used to predict bone strength, which becomes an invaluable tool for clinicians in patient treatment planning. This study developed specimen-specific micro-finite element (μFE) models using validated continuum-level models, containing grayscale-derived material properties, to indirectly establish tissue-level properties of porcine talar subchondral bone. Specimen-specific continuum finite element (hFE) models of subchondral trabecular bone were setup using μCT data of ten cylindrical specimens extracted from juvenile porcine tali. The models were validated using quasi-static uniaxial compression testing. Validated hFE models were used to calibrate the tissue modulus of corresponding μFE models by minimising the difference between the μFE and hFE stiffness values. Key trabecular morphological indices (BV/TV, DA, Conn.D, Tb.Th, EF) were evaluated. Good agreement was observed between hFE models and experiment (CCC = 0.66). Calibrated E_tiss was 504 ± 37.65 MPa. Average BV/TV and DA for μFE specimens were 0.37 ± 0.05 and 0.68 ± 0.11, respectively. BV/TV (r² = 0.667) correlated highly with μFE stiffness. The small intra-specimen variation to tissue-level properties suggests that variations to apparent-level stiffness originate from variations to microarchitecture rather than tissue mechanical properties.

Results of Trabecular-Metal Total Ankle Arthroplasties With Transfibular Approach

BACKGROUND

Total ankle arthroplasty is an alternative for arthrodesis. The objective of this study was to investigate the safety of trabecular-metal ankle prosthetic system with transfibular approach and external frame and its association with changes in clinical and functional scores.

METHODS

Between May 2013 and June 2017, a total of 104 consecutive patients underwent primary total ankle arthroplasty with a trabecular metal implant. The prospective clinical and radiographic data were collected. The mean follow-up time was 43.6 (14.6) months.

RESULTS

Of 104 patients, 88 (89%) reported improved functioning and 65 (66%) were very satisfied with the surgery. Of the patients, 51 (50%) did not report any pain at the end of follow-up at all. The average Kofoed score was 37.6 (SD 17.4) points at baseline and 74.8 (SD 20.6) points at the end of follow-up. There were 37 additional procedures, and the complication rate was nearly 20%.

CONCLUSION

Trabecular-metal total ankle prosthesis showed promising clinical results concerning pain and function. At 5-year follow-up, osteolysis and component loosening were rare.

LEVEL OF EVIDENCE

Level IV, case series.

Peri-prosthetic bone cysts after total ankle replacement. A systematic review and meta-analysis

BACKGROUND

Periprosthetic cystic osteolysis is a well-known complication of total ankle replacement. Several theories have been proposed for its aetiology, based on individual biomechanical, radiological, histopathology and outcome studies.

METHODS

Studies that met predefined inclusion/exclusion criteria were analysed to identify literature describing the presence of peri-prosthetic ankle cystic osteolysis. Quantitative data from the selected articles were combined and statistically tested in order to analyse possible relations between ankle peri-prosthetic bone cysts and specific implant characteristics.

RESULTS

Twenty-one articles were elected, totalizing 2430 total ankle replacements, where 430 developed peri-prosthetic cystic osteolysis. A statistically significant association (P<.001) was found between the presence of bone cysts and non-anatomic implant configuration, hydroxyapatite-coating, mobile-bearing and non tibial-stemmed implants. No significant association existed between the type of constraining and the presence of cysts (P>.05).

CONCLUSIONS

Non-anatomic, mobile-bearing, hydroxyapatite-coated and non tibial-stemmed total ankle replacements are positively associated with more periprosthetic bone cysts.

A COMPUTATIONAL STUDY OF DIFFERENT ADDITIVE MANUFACTURING-BASED TOTAL ANKLE REPLACEMENT DEVICES USING THREE-DIMENSIONAL HUMAN LOWER EXTREMITY MODELS WITH VARIOUS ANKLE POSTURES

Total ankle replacement (TAR) surgery is one of the useful methods to treat ankle arthritis. Selective laser melting that is an additive manufacturing (AM) technique has made it possible to fabricate orthopedic implants. However, there are rare studies to analyze AM implants using finite element method. Thus, the purpose of this study was to investigate the effect of the various porous designs with three types of tibial shapes for five ankle postures using three-dimensional (3D) human lower extremity models. The variable-axis-mobile-bearing (VAMB) TAR models were developed in one solid TAR design and three porous TAR designs on the tibial and talar components. Additionally, three shape designs (curved, flat, and tilted) of the tibial component were also evaluated. Each TAR design was assembled on the human lower extremity model with standing, inversion, eversion, plantar flexion, and dorsiflexion ankle postures. The results showed that there was a minor effect among the solid and porous TAR designs on the implant stability, the bone stress, and the implant stress. However, those performances in the plantar flexion were significantly reduced compared to that in the other ankle postures. Although the porous TAR designs have a higher risk of implant failure and bone breakage, it may have better bone-implant bonding ability. This study could help engineers and surgeons to understand the design rationale and biomechanics of AM-based TAR devices.

Total Ankle Arthroplasty: An Imaging Overview

With advances in implant technology, total ankle arthroplasty (TAA) has become an increasingly popular alternative to arthrodesis for the management of end-stage ankle arthritis. However, reports in the literature do not focus on the imaging features of TAA. Through a literature review, we demonstrate basic design features of the current ankle arthroplasty system, and the normal and abnormal postoperative imaging features associated with such devices. Pre- and postoperative evaluations of ankle arthroplasty mainly include radiography; in addition, computed tomography and magnetic resonance imaging provide further characterization of imaging abnormalities. Familiarization with multimodal imaging features of frequent procedural complications at various postoperative intervals is important in radiological practice.

Ankle Arthritis: You Can't Always Replace It

End-stage arthritis of the tibiotalar joint is disabling and causes substantial functional impairment. Most often it is the residual effect of a previous traumatic injury. Nonsurgical treatment of end-stage arthritis of the ankle includes bracing, shoe-wear modifications, and selective joint injections. For patients who fail to respond to nonsurgical modalities, the two primary treatment options are arthroplasty and arthrodesis. Each has its proponents. Although no ideal treatment of ankle arthritis exists, high-quality studies can help guide treatment in patients of varying demographics. Inherent risks are linked with each treatment option, but those of greatest concern are early implant loosening that requires revision following arthroplasty and the acceleration of adjacent joint degeneration associated with arthrodesis.

Failure modes for total ankle arthroplasty: a statistical analysis of the Norwegian Arthroplasty Register

BACKGROUND

It is imperative to understand the most common failure modes of total ankle arthroplasty (TAA) to appropriately allocate the resources, healthcare costs, enhancing surgical treatment methods, and improve design and longevity of the implant. The objective of this study was to investigate the primary mode or modes of failure (Loose talar component, loose tibial component, dislocation, instability, misalignment, deep infection, Fracture (near implant), Pain, defect polyethylene (PE), other, and missing information) of TAA implants, so these failure mode/modes can be targeted for future improvement.

METHODS

The Norwegian Total Hip Arthroplasty Register 2008 was chosen as the primary source of data since the register have been in existence for 20 years and also gives more specific failure modes than other registries. Tukey-Kramer method was applied to Norwegian Arthroplasty Register.

RESULTS

After the application of the Tukey-Kramer method, it is evident that there is no significant difference between any of the failure modes that are pertinent to the ankle. However, there is significant evidence that the number of ankle arthroplasties are increasing with time.

CONCLUSIONS

Since there is no statistical evidence showing which failure mode contributes most to revision surgeries, it is concluded that more information/data is needed to further investigate failure modes in ankle arthroplasties. Since the numbers of such surgeries are increasing, sufficient data should become available in time.

Thrombembolic complications after total ankle replacement

The literature addressing functional outcome and survivorship of prosthesis components is constantly growing. However, the data on thromboprophylaxis and thrombembolic complications in patients who underwent TAR are scarce. A total of 31 studies were included in the systemic literature review. The incidence of thrombembolic complications varied between 0.0 % and 9.8 %. Most commonly, low molecular weight heparin was used as thromboprophylaxis for 6 weeks postoperatively. The incidence of thrombembolic complications was comparable with that of symptomatic deep vein thrombosis in patients with total knee or hip replacement.

A review of the STAR prosthetic system and the biomechanical considerations in total ankle replacements

The ankle is a complex joint, anatomically and biomechanically. Pathologically diseased ankle joints, which require surgical intervention, now have the option of a total ankle replacement system rather than the long-standing arthrodesis procedure, first described by Albert in 1878. The anatomical features and forces acting across the joint are important when designing total ankle replacement (TAR) systems. This review discusses the history and evolution of TAR prosthetic systems and considers how the ankle's normal physiology and biomechanics is incorporated into their design. The Scandinavian total ankle replacement (STAR) is a three component prosthetic system and this review concludes that its size, shape and surgical insertion technique allows the biomechanical requirements of the ankle to be met with an adequate stress distribution in particular.

History and evolution in total ankle arthroplasty

INTRODUCTION

The current study provides an overview of history and evolution in total ankle arthroplasty.

METHODS

We conducted a comprehensive literature search without limitations to language. Information from any source, providing evidence of the use ankle of prostheses (e.g. biomechanical testing, cadaveric implantations or clinical use) was evaluated. Data regarding biomechanical concepts, design considerations, published results (patient numbers, surgical method, follow-up, complications and survival rates) were collected.

RESULTS

Only level IV studies were found. Mobile-bearing prostheses are mainly used in Europe, and fixed-bearing implants are mainly used in the USA. The current designs' failure rate is 10-12% at approximately 5 years. Survival rates vary among different institutions. Increased surgeons' experience is associated with better outcomes.

DISCUSSION

Biomechanical studies and review of previous implant failures has led to the development of a new generation of implants.

CONCLUSIONS

Results show that ankle arthroplasty is a viable alternative for the management of ankle arthritis in selected patients.