Total ankle arthroplasty. A long-term review of the London Hospital experience

Effect of novel polyethylene insert configurations on bone-implant micromotion and contact stresses in total ankle replacement prostheses: a finite element analysis

Purpose

This study investigates the impact of elastic improvements to the artificial ankle joint insert on prosthesis biomechanics to reduce the risk of prosthesis loosening in TAR patients.

Methods

CT data of the right ankle was collected from one elderly female volunteer. An original TAR model (Model A) was developed from CT images and the INBONE II implant system. The development of the new inserts adopts an elastic improvement design approach, where different geometric configurations of flexible layers are inserted into the traditional insert. The structure can be divided into continuous flexible layers and intermittent flexible layers. The flexible layers aim to improve the elasticity of the component by absorbing and dispersing more kinetic energy. The newly designed inserts are used to replace the original insert in Model A, resulting in the development of Models B-D. A finite element model of gait analysis was based by gait parameters. Discrepancies in micromotion and contact behaviour were analysed during the gait cycle, along with interface fretting and articular surface stress at 50% of the gait cycle.

Results

In terms of micromotion, the improved elastic models showed reduced micromotion at the tibial-implant interfaces compared to the original model. The peak average micromotion decreased by 12.1%, 13.1%, and 14.5% in Models B, C, and D, respectively. The micromotion distribution also improved in the improved models, especially in Model D. Regarding contact areas, all models showed increased contact areas of articular surfaces with axial load, with Models B, C, and D increasing by 26.8%, 23.9%, and 24.4%, respectively. Contact stress on articular surfaces increased with axial load, reaching peak stress during the late stance phase. Models with continuous flexible layer designs exhibited lower stress levels. The insert and the talar prosthetic articular surfaces showed more uniform stress distribution in the improved models.

Conclusion

Improving the elasticity of the insert can enhance component flexibility, absorb impact forces, reduce micromotion, and improve contact behavior. The design scheme of continuous flexible layers is more advantageous in transmitting and dispersing stress, providing reference value for insert improvement.

Quality of Outcomes Research in Total Ankle Arthroplasty

Total ankle arthroplasty is a topic that has recently gained increasing interest, largely due to the improved outcomes, which have been demonstrated by short- and mid-term research studies on the newer, third-generation implant designs. The purpose of this review is to provide an updated assessment of the quality of outcomes research on total ankle arthroplasty.

A numerical investigation of stress, strain, and bone density changes due to bone remodelling in the talus bone following total ankle arthroplasty

Total ankle arthroplasty is the gold standard surgical treatment for severe ankle arthritis and fracture. However, revision surgeries due to the in vivo failure of the ankle implant are a serious concern. Extreme bone density loss due to bone remodelling is one of the main reasons for in situ implant loosening, with aseptic loosening of the talar component being one of the primary reasons for total ankle arthroplasty revisions. This study is aimed at determining the performance and potential causes of failure of the talar component. Herein, we investigated the stress, strain, and bone density changes that take place in the talus bone during the first 6 months of bone remodelling due to the total ankle arthroplasty procedure. Computed tomography scans were used to generate the 3D geometry used in the finite element (FE) model of the Intact and implanted ankle. The Scandinavian Total Ankle Replacement (STAR™) CAD files were generated, and virtual placement within bone models was done following surgical guidelines. The dorsiflexion physiological loading condition was investigated. The cortical region of the talus bone was found to demonstrate the highest values of stress (5.02 MPa). Next, the adaptive bone remodelling theory was used to predict bone density changes over the initial 6-month post-surgery. A significant change in bone density was observed in the talus bone due to bone remodelling. The observed quantitative changes in talus bone density over 6-month period underscore potential implications for implant stability and fracture susceptibility. These findings emphasise the importance of considering such biomechanical factors in ankle implant design and clinical management.

Reflections on Presurgical and Postsurgical Gait Mechanics After 50 Years of Total Ankle Arthroplasty and Perspectives on the Next Decade of Advancement

Although not the most prevalent form of lower limb pathology, ankle arthritis is one of the most painful and life-limiting forms of arthritis. Developing from overuse and various traumatic injuries, the effect of ankle arthritis on gait mechanics and effective treatment options for ankle arthritis remain an area of extensive inquiry. Although nonsurgical options are common (physical therapy, limited weight-bearing, and steroidal injections), surgical options are popular with patients. Fusion remains a common approach to stabilize the joint and relieve pain. However, starting in the early 1970s, total ankle arthroplasty was proposed as an alternative to fusion.

[Update: endoprosthetics on the ankle joint]

The ankle joint has to bear the entire body weight on a relatively small joint surface. Incongruities, instabilities and deformities lead to painful arthrosis and considerable restrictions in everyday life. For many years, arthrodesis has proven to be the gold standard for end stage arthrosis; however, considering modern endoprostheses for the ankle joint it is no longer appropriate to offer only arthrodesis. The very good results of the 3rd generation 3‑component prostheses and the 4th generation 2‑component prostheses show how much the surgical treatment options for the ankle joint are currently changing. The simplified implantation techniques enable access to arthroplasty of the ankle joint for a broader spectrum of surgeons and explain the increasing implantation rates in recent years. Decisive for postoperative success are correct planning with knowledge of the leg axes and foot position, correct patient selection and exact surgical placement of the components.

Noninvasive Soft Tissue Expansion Strips and Wound Complications After Total Ankle Arthroplasty

BACKGROUND

Total ankle arthroplasty through the anterior approach (TAR-AA) is an increasingly popular treatment for ankle arthritis, but it carries a known risk for wound complications. Several products have been investigated to mitigate this risk; however, most are either costly or invasive. Noninvasive skin expansion strips (NSESs) were designed to transfer tension away from the incision and induce new skin growth at the edges of the strips. We hypothesize that postoperative application of NSESs will decrease unplanned clinic visits and wound complications after TAR-AA.

METHODS

This is a prospective cohort study of 41 patients at a single institution (3 surgeons) treated with NSESs after undergoing TAR-AA. An additional 41 consecutive historical patients treated without NSESs were retrospectively included as a control group. Patients received application of NSESs in the operating room after routine wound closure and again 2 weeks postoperatively. No other changes were made to the surgeons' wound closure technique, immobilization, follow-up timing, or rehabilitation protocols. Primary outcomes included (1) additional clinic visit required for wound assessment or suture removal, (2) superficial wound complication, and (3) deep infection.

RESULTS

Baseline demographics did not differ significantly from our 41 consecutively treated historical controls. Additional clinic visits for suture removal or wound evaluation were significantly lower for patients treated with NSESs (15%, 6 of 41) compared to the control group (49%, 20 of 41) (P = .001). There was also a significant difference in the superficial wound complication rate in the treatment group vs control group, 2% and 12%, respectively (P = .04). There were no deep infections in either group.

CONCLUSION

Noninvasive skin expansion strips placed after TAR-AA with an anterior approach have the potential to decrease wound complications and unplanned clinic visits. Further high-volume or randomized studies are needed to clarify their cost effectiveness and effect on long-term outcomes.

LEVEL OF EVIDENCE

Level II, prospective 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.

Mid-Term Functional and Radiological Outcomes of Total Ankle Replacement in an Asian Cohort

There are limited studies looking at longer-term outcomes of the total ankle replacement (TAR) in the Asian cohort. Asian ankles are smaller in size and are more varus compared to Western cohorts. Cultural differences also require increased ankle range of motion demands. Therefore, assessment of longer-term functional and radiological outcomes in the Asian cohort is warranted. Between 2007 and 2015, 43 consecutive patients received a 3-component, cementless, unconstrained, fully congruent TAR. Patients were followed up over a mean 8 (range 5-14 years). Preoperative and postoperative AOFAS ankle-hindfoot score (AOFAS-AHS), visual analogue score (VAS), physical and mental component scores of the SF-36 (PCS and MCS respectively) were calculated. European Foot and Ankle Score was also recorded at 8 years. Radiographs were reviewed postoperatively to assess implant position and study evidence of implant loosening and impingement. At 8 years, survivorship was 83.5%. Reasons for implant removal included infection (n = 2) and aseptic loosening (n = 5). AOFAS-AHS, VAS MCS at 8 years postoperatively were comparable to outcomes at 2 years postoperatively (p > .05). PCS at 8 years demonstrated improvement compared to 2 years postoperatively (49 ± 7 vs 42 ± 11, p = .048). Radiographic impingement was noted in 9 cases (20.9%). Radiological loosening was noted in 8 cases with 5 cases requiring revision surgery. At 8 years postoperatively, clinical outcomes, radiological outcomes and survivorship following TAR in an Asian cohort are satisfactory and comparable to that found in existing literature. Long-term studies are required to ascertain survivorship of TAR. Implant design with the Asian cohort in mind may yield improved outcomes.

Polka dot cementless talar component in enhancing total ankle replacement fixation: A parametric study using the finite element analysis approach

The primary stability of a total ankle replacement (TAR) is essential in preventing long-term aseptic loosening failure and could be quantified based on micromotion at the bone-prosthesis interface subjected to physiological loading during the normal walking. A 3D finite element analysis was conducted to investigate the current commercial STAR™ Ankle TAR bone-prosthesis interface relative micromotion (BPIRM) with addition of the talus bone minimum principal bone stresses (MPBS). Comparison was made to the proposed polka dot designs with the hemispheric feature that was demonstrated to enhance BPIRM. Parametric studies were conducted on the hemispheric features with changes in its diameter, length and shape. The FE results indicated high BPIRM at the talar component was primarily contributed by de-bonding (in the normal direction) between the talus bone and talar component. The MPBS were found to be most significant in the superior anterior and superior medial regions of the talus bone. When the pin length was increased from 1.5 to 3 mm, the BPIRM was predicted to fall below 50 μm in favour of bone in-growth. Based on the practicality of the prosthesis implantation during the surgical procedure, the final design that incorporated both the initial polka dot and 3 mm pin length in a crisscross manner was deemed to be a favorable design with reduced BPIRM and MPBS hence lowering the risk of long-term aseptic loosening.

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.

Outpatient total ankle replacement

INTRODUCTION

Since the development of the last generation of implants total ankle replacements (TAR) is becoming more and more popular in patients and in specialized surgeon teams, the trend for outpatient surgery is growing, and protocols now are well established for hip or knee replacement. We adapted a protocol for outpatient TAR and hypothesized that it could be performed safely as standard procedure.

PATIENTS AND METHODS

Twenty-five consecutive patients among 141 TAR were treated with our outpatient protocol relying on three fundamentals: bleed control, pain control, and autonomy. They received 1 g of tranexamic acid before surgery, and after discard from post-operative care unit, they were operated under long-lasting nerve block precociously relayed by oral NSAIDs and had an immediate full weight-bearing authorization at discharge.

RESULTS

No patients we readmitted for an acute care following TAR, especially for haematoma or uncontrolled pain. Mean VAS was < 1 before discharge from post-operative care unit and < 2 until day 90. One patient had a delayed wound healing treated surgically at day 30 without implant revision.

CONCLUSION

Outpatient TAR is possible and safe if a risk management process is used, and the three basic principles for outpatient procedures are respected: bleed control, pain control, and patient autonomy. We consider now this modality as a routine.

The reliability of radiographic measures of total ankle replacement position: an analysis from the OARS cohort

OBJECTIVE

There is no validated radiographic measurement to diagnose prosthetic complication(s) following total ankle replacements (TARs) although a number of angular and linear measurements, used to define the TAR position on postoperative radiographs, have been recommended to detect prosthetic loosening. The aim of this study was to test the intra- and interobserver reliability of these measurements.

MATERIALS AND METHODS

This is a prospective study embedded within a multicentre cohort study. Following sample size calculation, 62 patients were analysed. Six measurements were performed on the first postoperative anteroposterior and lateral ankle radiographs: angles α and β, and length "a" defined the craniocaudal position of the tibial component, while angle γ, and lengths "b" and "c" defined the angular position of the talar component. Measurements were recorded by three independent observers. Inter- and intraobserver reliability was assessed with intraclass correlation coefficient (ICC), Bland-Altman plots, and within-subject coefficients of variation (CV).

RESULTS

The intrarater ICC was "almost perfect" (ICC 0.83-0.97) for all six measurements. The interrater ICC was "substantial" to "almost perfect" (ICC 0.69-0.93). The mean difference in intrarater angular measurements was ≤ 0.6° and ≤ 0.8 mm for linear measurements, and ≤ 2.2° and ≤ 2.1 mm for interrater measurements. Maximum CV for the interrater linear measurements (≤ 17.7%) more than doubled that of the angular measurements (≤ 8.0%). The maximum width of the 95% limits of agreement was 6.5° and 8.4 mm for intrarater measures, and 8.9° and 10.6 mm for interrater measurements.

CONCLUSION

Angular measures are more reliable than linear measures and have potential in routine clinical practice for TAR position assessment.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Level III, comparative study.

Pathogenesis, Evaluation, and Management of Osteolysis Following Total Ankle Arthroplasty

Periprosthetic osteolysis is a common occurrence after total ankle arthroplasty (TAA) and poses many challenges for the foot and ankle surgeon. Osteolysis may be asymptomatic and remain benign, or it may lead to component instability and require revision or arthrodesis. In this article, we present a current and comprehensive review of osteolysis in TAA with illustrative cases. We examine the basic science principles behind the etiology of osteolysis, discuss the workup of a patient with suspected osteolysis, and present a review of the evidence of various management strategies, including grafting of cysts, revision TAA, and arthrodesis.Level of Evidence: Level V, expert opinion.

Does Coronal Plane Malalignment of the Tibial Insert in Total Ankle Arthroplasty Alter Distal Foot Bone Mechanics? A Cadaveric Gait Study

BACKGROUND

Total ankle arthroplasty (TAA) is becoming a more prevalent treatment for end-stage ankle arthritis. However, the effects of malalignment on TAA remain poorly understood.

QUESTIONS/PURPOSES

The purpose of this study was to quantify the mechanical effects of coronal plane malalignment of the tibial insert in TAA using cadaveric gait simulation. Specifically, we asked, is there a change in (1) ankle joint congruency, (2) kinematic joint position, (3) kinematic ROM, (4) peak plantar pressure, and (5) center of pressure with varus and valgus malalignment?

METHODS

A modified TAA was implanted into seven cadaveric foot specimens. Wedges were used to simulate coronal plane malalignment of the tibial insert. The degree of malalignment (tibial insert angle [TIA] and talar component angle [TCA]) was quantified radiographically for neutral and 5°, 10°, and 15° varus and valgus wedges. Dynamic walking at 1/6 of physiological speed was simulated using a robotic gait simulator. A motion capture system was used to measure foot kinematics, and a pressure mat was used to measure plantar pressure. Joint congruency was quantified as the difference between TIA and TCA. Continuous joint position, joint ROM, peak plantar pressure, and center of pressure for varus and valgus malalignment compared with neutral alignment were estimated using linear mixed effects regression. Pairwise comparisons between malalignment conditions and neutral were considered significant if both the omnibus test for the overall association between outcome and malalignment and the individual pairwise comparison (adjusted for multiple comparisons within a given outcome) had p ≤ 0.05.

RESULTS

Descriptively, the TIA and TCA were both less pronounced than the wedge angle and component incongruence was seen (R = 0.65; p < 0.001). Varus malalignment of the tibial insert shifted the tibiotalar joint into varus and internally rotated the joint. The tibiotalar joint's ROM slightly increased as the TIA shifted into varus (1.3 ± 0.7° [mean ± SD] [95% confidence interval -0.7 to 3.4]; p = 0.03), and the first metatarsophalangeal joint's ROM decreased as the TIA shifted into varus (-1.9 ± 0.9° [95% CI -5.6 to 1.7]; p = 0.007). In the sagittal plane, the naviculocuneiform joint's ROM slightly decreased as the TIA shifted into varus (-0.9 ± 0.4° [95% CI -2.1 to 0.3]; p = 0.017). Hallux pressure increased as the TIA became more valgus (59 ± 50 kPa [95% CI -88 to 207]; p = 0.006). The peak plantar pressure slightly decreased in the third and fourth metatarsals as the TIA shifted into valgus (-15 ± 17° [95% CI -65 to 37]; p = 0.03 and -8 ± 4° [95% CI -17 to 1]; p = 0.048, respectively). The fifth metatarsal's pressure slightly decreased as the TIA shifted into valgus (-18 ± 12 kPa [95% CI -51 to 15]) or varus (-7 ± 18 kPa [95% CI -58 to 45]; p = 0.002). All comparisons were made to the neutral condition.

CONCLUSIONS

In this cadaver study, coronal plane malalignment in TAA altered foot kinematics and plantar pressure. In general, varus TAA malalignment led to varus shift and internal rotation of the tibiotalar joint, a slight increase in the tibiotalar ROM, and a slight decrease in the first metatarsophalangeal ROM, while a valgus TAA malalignment was manifested primarily through increased hallux pressure with a slight off-loading of the third and fourth metatarsals.

CLINICAL RELEVANCE

This study may increase our understanding of the biomechanical processes that underlie the unfavorable clinical outcomes (such as, poor patient-reported outcomes or implant loosening) that have been associated with coronal plane malalignment of the tibial component in TAA.

Finite element analysis of bone-prosthesis interface micromotion for cementless talar component fixation through critical loading conditions

The total ankle replacement (TAR) survivability rate is still suboptimal, and this leads to many orthopaedic surgeons opting arthrodesis as a better option for the ankle arthritis patients. One of the fundamental reasons is due to the lack of primary stability of the prosthesis fixation at the bone-prosthesis interface hence leading to long-term aseptic loosening of the talar component. The commercially available Scandinavian Total Ankle Replacement (STAR) Ankle design and several additional design features (including trabecular metal, side fin, double fin, and polka-dot designs) were studied using finite element analysis, and the bone-prosthesis interface relative micromotion (BPIRM) and talar bone minimum principal stresses were examined and analysed. Three loading conditions at a gait cycle of heel strike, midstance, and toe off with different meniscal bearing displacement were also included as part of the study parameters. The results were correlated to in vitro cadaveric measurements and reported clinical studies. Simulated results showed that the de-bonding relative distance between the bone and prosthesis upon loading (COPEN defined by the simulation software) was the main reason constituting to the high interface micromotion between the talar component and talus bone (which could lead to long-term aseptic loosening). The polka-dot design was shown to induce the lowest BPIRM among all the designs studied.

Complications and results of the arthrodesis after total ankle arthroplasty failure: a retrospective monocentric study of 12 cases

INTRODUCTION

Total ankle arthroplasty (TAA) has the objective to maintain the range of motion of the tibiotarsal joint and to preserve the nearby joints. However, the complication rate and failures remain quite high after TAA. The main objective of the study was to evaluate the improvement in the functional scores of the tibiotarsal arthrodesis after TAA failure. The secondary objective was to assess the specific complications.

MATERIALS AND METHODS

This monocentric retrospective series includes 12 patients (nine men, three women, average age 52.5 years) operated between 2003 and 2018. An iliac graft was used in all cases. The arthrodesis was stabilized either by screws or by retrograde nailing.

RESULTS

The reoperation was due to painful malleolar conflicts or loosening. The AOFAS score increased from 38/100 to 67/100 (51-86) post-operatively. The fusion was acquired at 3.7 months (3-6) except in two cases.

DISCUSSION AND CONCLUSION

The 83% primary fusion rate is in the low average of the literature and 92% fusion rate in the high average after reoperation. All patients were improved even in two non-unions. The results of this study confirm that the arthrodesis after TAA failure is a reliable alternative to the TAA replacement. However, they are lower than those after a first-line arthrodesis.

Optimizing Outpatient Total Ankle Replacement from Clinic to Pain Management

Outpatient total ankle arthroplasty is a potential significant source of cost savings. The ability to institute an effective outpatient total ankle program depends on appropriate patient selection, surgeon experience with total ankle replacement, addressing preoperative patient expectations, the involvement of an experienced multidisciplinary care team including experienced anesthesiologists, nurse navigators, recovery room nursing staff and physical therapists, and most importantly, such a program requires complete institutional logistical support.

Design Rationale for Total Ankle Arthroplasty Systems: An Update

The design of total ankle arthroplasty systems is evolving as a result of findings from longer-term studies. Our understanding of modes of failure has increased, and surgical techniques have become more refined. Currently, five total ankle arthroplasty systems are used in the United States. The landscape has changed considerably in the decade since the latest article reviewing total ankle design was published. Some implants with acceptable intermediate results had much poorer outcomes at 7- to 10-year follow-up. As more research showing mid- to long-term outcomes is published, the design rationale and current outcomes data for each of these implants must be considered.

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

BACKGROUND

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

METHODS

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

RESULTS

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

DISCUSSION

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

CONCLUSION

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

Midterm Results of the Salto Talaris Total Ankle Arthroplasty

BACKGROUND

The Salto Talaris total ankle replacement is a modern fixed-bearing implant used to treat symptomatic ankle arthritis with the goals of providing pain relief, restoring mechanical alignment, and allowing motion of the ankle joint. The goal of this study was to report the midterm clinical results of one of the largest cohort of patients in the United States who underwent ankle replacement with this prosthesis.

METHODS

This is a review of patients with a minimum of 5 years up to 10 years' follow-up. At the preoperative visit and each annual assessment, patients rated their current level of pain using the visual analog score (VAS) and reported their functional level using the American Orthopaedic Foot & Ankle (AOFAS) ankle-hindfoot scores, the Short Musculoskeletal Function Assessment (SMFA), and the Short Form-36 (SF-36) Health survey. These scores were analyzed to assess differences between their levels preoperatively, 1 year postoperatively, and at their most recent follow-up. Criteria for failure was defined as revision requiring exchange or removal of the metallic components for any reason. We identified 106 patients having a Salto Talaris total ankle replacement. Seventy-two patients (mean age, 61.9 years) met the minimum requirement for follow-up (range 60-115 months, mean 81.1 months).

RESULTS

Significant improvements were seen in the VAS, SMFA, AOFAS score, and SF-36 from preoperatively to their final follow-up ( P < .001). Survivorship was 95.8% for those with at least 5-year follow-up, with 2 patients undergoing revision arthroplasty for aseptic loosening and a third patient scheduled for revision for a chronic wound infection. Fourteen patients (19%) required an additional surgery for a total of 17 additional operative procedures on the ipsilateral ankle or hindfoot.

CONCLUSION

Patients undergoing total ankle arthroplasty with the Salto Talaris prosthesis continued to show significant improvements in pain and functional outcomes at midterm follow-up. This prosthesis has shown to be an effective treatment option with durable results.

LEVEL OF EVIDENCE

Level IV, therapeutic, case series.

Role of Total Ankle Arthroplasty in Stiff Ankles

BACKGROUND

The decision tree for the operative treatment of end-stage ankle arthritis involves either ankle arthrodesis (AA) or total ankle arthroplasty (TAA). Although both have documented success providing diminished pain, improved patient-centered outcomes, and improved objective measures of function, arthroplasty is unique in its ability to preserve motion at the tibiotalar joint. Arthroplasty procedures are normally thought of as a motion-sparing surgery rather than a motion-producing procedure, which may limit its success in patients with stiff ankles. Our hypothesis was that there would be improvements in parameters of gait even in patients with a low degree of preoperative total sagittal range of motion.

METHODS

A retrospective review was conducted on patients who underwent total ankle arthroplasty with greater than 1-year follow-up. Seventy-six patients were available who underwent isolated TAA for end-stage ankle arthritis with greater than 1-year follow-up. Patient demographics and preoperative and postoperative gait analyses were evaluated. Using a linear regression model, the effect sizes for the variables of age, gender, BMI, preoperative diagnosis, and preoperative total sagittal range of motion were calculated. Multivariate analysis was used to determine the influence each individual variable had on the many parameters of preoperative gait, postoperative gait, and change in gait after surgery. A post hoc analysis was conducted in which patients were divided into 4 quartiles according to preoperative range of motion. A 1-way analysis of variance (ANOVA) was used to compare improvement in parameters of gait for the 4 subgroups.

RESULTS

Although a greater degree of preoperative sagittal range of motion was predictive of greater postoperative sagittal range of motion, patients with limited preoperative range of motion experienced a greater overall improvement in range of motion, and clinically meaningful absolute improvements in range of motion, and other parameters of gait. The post hoc analysis demonstrated that patients in the lowest quartile of preoperative motion had both statistically and clinically significant greater improvements across numerous parameters of gait, although the absolute values were lower than in the patients with higher preoperative ROM. Age, gender, BMI, and preoperative diagnosis did not correlate with changes in parameters of gait after total ankle arthroplasty.

CONCLUSION

Preoperative range of motion was predictive of overall postoperative gait function. On one hand, a low preoperative range of motion resulted in a lower absolute postoperative function. On the other hand, patients with stiff ankles preoperatively had a statistically and clinically greater improvement in function as measured by multiple parameters of gait. This suggests that total ankle arthroplasty can offer clinically meaningful improvement in gait function and should be considered for patients with end-stage tibiotalar arthritis even in the setting of limited sagittal range of motion.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Reconstruction of the distal tibia following resection of aggressive bone tumours using a custom-made megaprosthesis

OBJECTIVE

Largest, single-centre study of clinical and functional outcomes of patients who underwent endoprosthetic replacement (EPR) for aggressive distal tibial bone tumours.

METHOD

Retrospective observational study of eight patients was undertaken.

RESULTS

Median follow-up was 77 months (range 13-276). Cumulative five and ten year survival was 63% and 42% respectively. Three patients developed either disease recurrence or metastases post-surgery. One patient developed deep infection requiring washout and suppressive antibiotics. No patients required revision surgery. The median MSTS score at last follow up was 66%.

CONCLUSIONS

EPR of the distal tibia is a viable option and provides good function outcomes.

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.

Kinematics and Function of Total Ankle Replacements Versus Normal Ankles

End-stage ankle arthritis produces severe functional disability, quantifiable by gait abnormalities. In all categories of gait parameters, total ankle arthroplasty (TAA) satistically significantly improves function, compared to patients' preoperative function. There are increases in step length, cadence and velocity; in sagittal plane motion of the ankle, as well has hip and knee motion, and in ankle power and moment. These functional gait improvements correspond to clinical improvements of pain relief and satisfaction. Although these improvements fail to reach the functional performance of healthy controls, the improvement over preoperative function is clinically meaningful and statistically significant.

Dealing with the Stiff Ankle: Preoperative and Late Occurrence

In patients with a stiff ankle replacement, appropriate resection of scarred capsular structures, hypertrophic bone debridement, and careful release of tendons should be performed to achieve good outcomes. Appropriately sized and correctly implanted components are required to restore ankle function to as normal as possible. Although not proven, the better a total ankle replacement is balanced, the less likely scar and heterotopic bone formation will occur. In patients with a stiff and painful ankle replacement, a preoperative diagnostic workup is mandatory to understand the underlying pathologic process and plan appropriate treatment. All underlying causes should be addressed.

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.

Total ankle arthroplasty versus ankle arthrodesis

Aims

Few reports compare the contribution of the talonavicular articulation to overall range of movement in the sagittal plane after total ankle arthroplasty (TAA) and tibiotalar arthrodesis. The purpose of this study was to assess changes in ROM and functional outcomes following tibiotalar arthrodesis and TAA.

Patients and Methods

Patients who underwent isolated tibiotalar arthrodesis or TAA with greater than two-year follow-up were enrolled in the study. Overall arc of movement and talonavicular movement in the sagittal plane were assessed with weight-bearing lateral maximum dorsiflexion and plantarflexion radiographs. All patients completed Short Form-12 version 2.0 questionnaires, visual analogue scale for pain (VAS) scores, and the Foot and Ankle Ability Measure (FAAM).

Results

In all, 41 patients who underwent TAA and 27 patients who underwent tibiotalar arthrodesis were enrolled in the study. The mean total arc of movement was 34.2° (17.0° to 59.1°) with an average contribution from the talonavicular joint of 10.5° (1.2° to 28.8°) in the TAA cohort. The average total arc of movement was 24.3° (6.9° to 44.3°) with a mean contribution from the talonavicular joint of 22.8° (5.6° to 41.4°) in the arthrodesis cohort. A statistically significant difference was detected for both total sagittal plane movement (p = 0.00025), and for talonavicular motion (p < 0.0001). A statistically significant lower VAS score (p = 0.0096) and higher FAAM (p = 0.01, p = 0.019, respectively) was also detected in the TAA group.

Conclusion

TAA preserves more anatomical movement, has better pain relief and better patient-perceived post-operative function compared with patients undergoing fusion. The relative increase of talonavicular movement in fusion patients may play a role in the outcomes compared with TAA and may predispose these patients to degenerative changes over time. Take home message: TAA preserves more anatomic sagittal plane motion and provides greater pain relief and better patient-perceived outcomes compared with ankle arthrodesis. Cite this article: Bone Joint J 2016;98-B:634–40.

Gutter Impingement in Total Ankle Arthroplasty

Gutter pain and impingement are recognized entities following total ankle arthroplasty (TAA). However, little concrete information is available in the existing literature regarding the etiology, potentiating factors, treatment and prevention of gutter disease. This comprehensive monograph discusses this problem in expansive detail and provides insight to surgeons who perform TAA, such that these complications can be minimized in the future.

LEVELS OF EVIDENCE

Level V: Expert opinion.

Radiographic Outcomes of a Mobile-Bearing Total Ankle Replacement

BACKGROUND

Contemporary total ankle prostheses embody design changes intended to address weaknesses in first-generation implants. Due to these changes, outcomes of the newer designs are of particular interest. We have previously published self-reported patient outcomes for the STAR (Scandinavian Total Ankle Replacement) prosthesis. The present study documents radiographic outcome measurements for the STAR prosthesis at intermediate to long-term follow-up.

METHODS

Of 89 consecutive ankle replacements performed between July 1998 and April 2007, 79 had a minimum follow-up of 2 years and were followed prospectively. Serial radiographs were measured by 2 of the authors, including varus, valgus, alpha, beta, and gamma angles, as well as point contact ratio. Inter- and intrarater reliability was calculated and reported. A "severe" subgroup of patients with preoperative coronal plane deformity exceeding 10 degrees was assessed separately. Preoperative and immediate postoperative measurements were compared and maintenance of correction evaluated on subsequent radiographs. Heterotopic ossification and pericomponent lucency were documented and followed, and subsequent procedures were recorded to follow survivorship. The mean follow-up was 8.0 years.

RESULTS

Of the 79 ankles, 25 underwent a secondary surgery (31.6%). Coronal correction averaged 5.1 degrees (P < .001), and this was maintained to final follow-up. The severe subgroup (n = 21), with a mean preoperative coronal angulation of 16.1 degrees, was corrected to 4.6 degrees at final follow-up (P < .001). The severe subgroup had a higher secondary surgery rate at 33.3%, with metallic component revision or failure occurring in 3 cases (14.3%) compared to 8 (10.1%) in the entire cohort. The heterotopic ossification rate was 100%, slightly higher than prior reports.

CONCLUSIONS

STAR prosthesis survivorship was similar to that documented in prior studies of second-generation implants in European patient cohorts. Statistically significant correction in coronal alignment was achieved immediately after surgery and maintained until a final mean follow-up of 8 years, even in patients with preoperative deformity greater than 10 degrees.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Articular congruency of the Salto Talaris total ankle prosthesis

BACKGROUND

The Salto-Talaris polyethylene articulating surface was designed to allow, but limit accessory motion. This investigation examines surface characteristics between the polyethylene bearing and anatomic talar component in various positions of function.

METHODS

A Salto Talaris talar prosthesis and matching polyethylene bearing were scanned to create digital solid body models and manipulated to assess surface contact during simulated gait. With computer micromanipulation of the component positions, the surface intersections were recorded for 15 different alignments.

RESULTS

The Salto Talaris has limited contact congruity with four points of contact in dorsiflexion, neutral, and plantarflexion. Lateral and medial translations showed only 2-point contact. The radii of curvatures between the talar component and polyethylene surfaces do not match. There was no sulcus contact yet component separation distance was small, suggesting increased loads.

CONCLUSION

Surface incongruency was measured based on computer model analysis which raises a concern of increased contact pressures.

Functional and radiological outcome of periprosthetic fractures of the ankle

The incidence of periprosthetic fractures of the ankle is increasing. However, little is known about the outcome of treatment and their management remains controversial. The aim of this study was to assess the impact of periprosthetic fractures on the functional and radiological outcome of patients with a total ankle arthroplasty (TAA).

A total of 505 TAAs (488 patients) who underwent TAA were retrospectively evaluated for periprosthetic ankle fracture: these were then classified according to a recent classification which is orientated towards treatment. The outcome was evaluated clinically using the American Orthopedic Foot and Ankle Society (AOFAS) score and a visual analogue scale for pain, and radiologically.

A total of 21 patients with a periprosthetic fracture of the ankle were identified. There were 13 women and eight men. The mean age of the patients was 63 years (48 to 74). Thus, the incidence of fracture was 4.17%.

There were 11 intra-operative and ten post-operative fractures, of which eight were stress fractures and two were traumatic. The prosthesis was stable in all patients. Five stress fractures were treated conservatively and the remaining three were treated operatively.

A total of 17 patients (81%) were examined clinically and radiologically at a mean follow-up of 53.5 months (12 to 112). The mean AOFAS score at follow-up was 79.5 (21 to 100). The mean AOFAS score in those with an intra-operative fracture was 87.6 (80 to 100) and for those with a stress fracture, which were mainly because of varus malpositioning, was 67.3 (21 to 93). Periprosthetic fractures of the ankle do not necessarily adversely affect the clinical outcome, provided that a treatment algorithm is implemented with the help of a new classification system.

Cite this article: Bone Joint J 2015;97-B:950–6.

Current Concepts in the Management of Ankle Osteoarthritis: A Systematic Review

Ankle osteoarthritis is less common than hip or knee osteoarthritis; however, it is a relatively common presentation and is predominantly related to previous trauma. Treatments have traditionally consisted of temporizing measures such as analgesia, physiotherapy, and injections until operative treatment in the form of arthrodesis is required. More recently, interest has been increasing in both nonoperative and alternative operative options, including joint-sparing surgery, minimal access arthrodesis, and new arthroplasty designs. The present systematic instructional review has summarized the current evidence for the treatment options available for ankle osteoarthritis.

Preoperative and Postoperative Range of Motion: A Retrospective Comparison of Two Total Ankle Replacement Systems

The purpose of the present report was to compare the range of motion between a total ankle replacement requiring arched bony resection and a total ankle replacement requiring a flat cut for implantation. We hypothesized that the arched contour would more closely mimic the patient's pre-existing anatomy and increase the range of motion. Pain was evaluated as a secondary outcome. Twenty-eight patients (age 55.95 ± 15.29 years) were included. Of the 28 patients, 14 were treated with an arch cut and 14 with a flat cut. Although no significant difference was found in dorsiflexion between the 2 implant groups (p = .38), preoperative dorsiflexion, body mass index, implant type, and preoperative plantarflexion emerged as significant predictors of postoperative plantarflexion (p = .04). This finding indicates that postoperative plantarflexion was significantly greater in patients treated with an arch cut (30.43° ± 10.01°) than a flat cut (21.79° ± 15.70°, p = .02), when controlling for the other explanatory variables. A statistically significant improvement in pain was observed after total ankle replacement (p < .001). The mean change in pain was similar for the 2 implant groups when statistically controlling for the follow-up duration (p = .09). The findings from the present report suggest that plantarflexion significantly improves after total ankle replacement requiring an arched cut for implantation. Future studies should be designed to control for potentially confounding variables and assess the differences in range of motion after total ankle replacement.

Is end-stage ankle arthrosis best managed with total ankle replacement or arthrodesis? A systematic review

Introduction. End-stage ankle osteoarthritis is a debilitating condition. Traditionally, ankle arthrodesis (AA) has been the surgical intervention of choice but the emergence of total ankle replacement (TAR) has challenged this concept. This systematic review aims to address whether TAR or AA is optimal in terms of functional outcomes. Methods. We conducted a systematic review according to PRISMA checklist using the online databases Medline and EMBASE after January 1, 2005. Participants must be skeletally mature and suffering from ankle arthrosis of any cause. The intervention had to be an uncemented TAR comprising two or three modular components. The comparative group could include any type of ankle arthrodesis, either open or arthroscopic, using any implant for fixation. The study must have reported at least one functional outcome measure. Results. Of the four studies included, two reported some significant improvement in functional outcome in favour of TAR. The complication rate was higher in the TAR group. However, the quality of studies reviewed was poor and the methodological weaknesses limited any definitive conclusions being drawn. Conclusion. The available literature is insufficient to conclude which treatment is superior. Further research is indicated and should be in the form of an adequately powered randomised controlled trial.

Functional results and complication analysis after total ankle replacement: early to medium-term results from a Portuguese and Spanish prospective multicentric study

BACKGROUND

Ankle arthroplasty is increasingly being used to treat end-stage ankle osteoarthritis.

METHODS

Between January 2005 and January 2011, 159 patients have been included in an ongoing prospective multicentric study analysing the results of total ankle arthroplasty in Portugal and Spain. 119 patients (119 replacements) were available for review and were evaluated for range of motion (ROM), clinical status (American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score), complications and survivorship rate.

RESULTS

Mean follow-up was 39 months. A total of 17 complications were reported, with 7 leading to subsequent surgery (94.1% survivorship rate). Of these, there were two infections (98.3% survivorship rate), two painful subtalar arthritis, one instability, one malalignment and one tibial bone cyst. Complications not requiring further surgery were 6 intra-operative malleolar fractures and 4 cases of skin necrosis.

CONCLUSIONS

Adequate patient selection and a thorough knowledge of the surgical technique are mandatory to reduce the number of complications and increase ankle arthroplasty survivorship.

Comparison of sagittal subluxation in two different three-component total ankle replacement systems

BACKGROUND

Malalignment following total ankle arthroplasty (TAA) has been reported in 4% to 45% of patients. However, all reports to date have been related to coronal deformity. This study compared sagittal malalignment between the Mobility and Hintegra total ankle systems and assessed the positional stability of the implant components over time.

METHODS

The study included 50 cases each of total ankle replacement arthroplasty with the Hintegra and Mobility total ankle systems performed between May 2008 and June 2010. The Mobility group included 24 men and 25 women, and the mean age was 60.3 years (range, 50.7-70.0 years). The Hintegra group included 25 men and 25 women, and the mean age was 59.8 years (range, 50.8-68.7 years). The 2 groups did not differ in terms of gender (P = .76) or age (P = .77). Three independent observers with different levels of training evaluated the radiographs and performed the measurements independently. Each observer evaluated the radiographs twice at a 6-week interval to determine the intraobserver reliability, and the anteroposterior offset ratio was evaluated.

RESULTS

The anteroposterior offset ratio intra- and interobserver reliabilities all showed good or excellent levels of agreement in the Hintegra total ankle system and the Mobility total ankle system. With respect to the stability of sagittal translation of the talus, the Mobility system (0.08 ± 0.07 immediately, 0.0 ± 0.07 at 6 weeks postoperatively, and 0.01 ± 0.07 at 1 year postoperatively) was better than the Hintegra system (0.20 ± 0.08 immediately, 0.18 ± 0.11 at 6 weeks postoperatively, and 0.15 ± 0.10 at 1 year postoperatively) (P < .0001).

CONCLUSIONS

The Mobility system had less sagittal malalignment of the talus than the Hintegra system. Consequently, when treating ankles in patients with osteoarthritis using the Hintegra system, one must pay careful attention to sagittal malalignment during surgery.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Total ankle arthroplasty in end-stage ankle arthritis

Recent advancements in ankle prosthesis design, combined with improved surgical techniques for correction of coronal plane deformity and ligamentous balancing, have led to a resurgence of interest in total ankle arthroplasty for the treatment of end-stage ankle arthritis. Although ankle arthrodesis has long been considered the gold standard treatment for ankle arthritis, recent studies have shown that patients who undergo total ankle replacement have equivalent pain relief and improved function, when compared with patients with an ankle fusion. The purpose of this review is to summarize the indications, advantages, disadvantages, and clinical outcomes of some of the more commonly used modern prostheses for total ankle arthroplasty.

[Arthrodesis and endoprostheses of the ankle joint: indications, techniques and pitfalls]

If adequate conservative measures for the treatment of end-stage ankle osteoarthritis have failed, surgery may be taken into consideration. After exorbitant failure rates in the beginning of total ankle replacement, nowadays this kind of treatment has regained lot of interest and has become a viable alternative to ankle fusion. The correct indication and a precise explanation of the surgical procedure, outcomes and potential complications provide a solid base for future success.Currently, there is no doubt that total ankle replacement has become an important player in the treatment of symptomatic and debilitating end-stage ankle arthritis. With increasing number of patients who undergo total ankle replacement the experience with this kind of procedure increases too. As a consequence several surgeons have started to stretch indications favoring total ankle replacement. However, it must be mentioned here, despite progress in terms of improved anatomical and biomechanical understanding of the hindfoot and improved surgical techniques and instruments, total ankle replacement and ankle fusion remain challenging and difficult procedures. We provide a review article including an overview of the relevant techniques. This article should serve as rough guide for surgeons and help in decision-making regarding total ankle replacement and ankle fusion.

Incidence of rheumatoid arthritis-related ankle replacement and ankle arthrodesis: a Finnish nationwide register-based study from 1997–2010

BACKGROUND AND PURPOSE

For 20 years, medical treatment of rheumatoid arthritis (RA) has been improving and the incidence of joint surgery has decreased. We investigated the rates of primary ankle joint arthrodesis and total ankle arthroplasty in patients with RA in Finland between 1997 and 2010 to establish whether trends have changed during that period.

METHODS

The annual figures for primary ankle joint arthrodeses and total ankle replacements performed in patients with RA were obtained from nationwide population-based registries. Incidences were calculated per population of 10(5) and they are reported in 2-year periods.

RESULTS

During the study period, 593 primary ankle joint arthrodeses and 318 total ankle arthroplasties were performed in patients with RA. The incidence of ankle joint arthrodesis reached its highest value (2.4/10(5)) in 1997-1998 and it was lowest in 2001-2002 (1.1/10(5)). After 2002, the incidence increased slightly but did not reach the level in 1997-1998, even though total ankle replacements almost ended in Finland during the period 2009-2010. From 1997, total ankle replacements increased until 2003-2004 (incidence 1.5/10(5)) and then gradually decreased. In 2009-2010, the incidence of total ankle replacements was only 0.4/10(5).

INTERPRETATION

During the observation period 1997-2010, while total ankle replacements generally became more common in patients with RA, the incidence of primary ankle joint arthrodesis decreased and did not increase in the period 2009-2010, even though total ankle replacement surgery almost ended in Finland. No change in the incidence of these operations, when pooled together, was observed from 1997 to 2010.

Comparison of the HINTEGRA and Mobility total ankle replacements

In a retrospective study we compared 32 HINTEGRA total ankle replacements (TARs) and 35 Mobility TARs performed between July 2005 and May 2010, with a minimum follow-up of two years. The mean follow-up for the HINTEGRA group was 53 months (24 to 76) and for the Mobility group was 34 months (24 to 45). All procedures were performed by a single surgeon.

There was no significant difference between the two groups with regard to the mean AOFAS score, visual analogue score for pain or range of movement of the ankle at the latest follow-up. Most radiological measurements did not differ significantly between the two groups. However, the most common grade of heterotopic ossification (HO) was grade 3 in the HINTEGRA group (10 of 13 TARs, 76.9%) and grade 2 in the Mobility group (four of seven TARs, 57.1%) (p = 0.025). Although HO was more frequent in the HINTEGRA group (40.6%) than in the Mobility group (20.0%), this was not statistically significant (p = 0.065).The difference in peri-operative complications between the two groups was not significant, but intra-operative medial malleolar fractures occurred in four (11.4%) in the Mobility group; four (12.5%) in the HINTEGRA group and one TAR (2.9%) in the Mobility group failed (p = 0.185).

Cite this article: Bone Joint J 2013;95-B:1075–82.

Outcome after total ankle arthroplasty-results and findings from worldwide arthroplasty registers

PURPOSE

The data currently available concerning total ankle arthroplasty (TAA) does not allow valid conclusions in several clinically relevant areas. Total ankle arthroplasty imposes special requirements on the methodology of data collection, evaluation, publication and the assessment of register data.

METHODS

We undertook a structured and descriptive analysis of all outcome data available from high-quality national arthroplasty registers worldwide. Register data from Sweden, Finland, Norway, New Zealand and Australia were included in the analysis.

RESULTS

There are marked differences between Europe and Oceania with respect to indications. All data sets show revision rates of approximately 10 % at five years, of which about 40 % of cases are for aseptic loosening. Inlay fractures are relatively common, which indicates potential for the improvement of implants. The documentation of intraoperative surgical errors leading to revision surgery varies significantly among registers. A relevant number of complications are treated without an implant component being exchanged and therefore not covered by a register.

CONCLUSIONS

The results of TAA are promising, but the revision rate is higher than for total hip or knee arthroplasty. TAA outcome measurement by means of registers has several specific requirements necessitating additional documentation beyond the basic data set. For methodological reasons the evaluation of results is more complex than for hip or knee arthroplasty. It will therefore be essential to standardise data collection and evaluation and develop a methodology addressing the specific needs of TAA.

Failure modes of current total ankle replacement systems

Methodology for evaluation of total ankle replacements is described. Fusion and its problems are discussed as are those of total ankle joint replacement. Fusion is an imperfect solution because it reduces ankle functionality and has significant complications. Early fixed-bearing total ankles were long-term failures and abandoned. Currently available fixed-bearing ankles have proved inferior to fusion or are equivalent to earlier devices. Only mobile-bearing devices have been shown reasonably safe and effective. One such device, the STAR, has been approved by the Food and Drug Administration after a rigorous controlled clinical trial and is available for use in the United States.

Tibio-talo-calcaneal arthrodesis with retrograde compression intramedullary nail fixation for salvage of failed total ankle replacement: a systematic review

Failed total ankle replacement is a complex problem that should only be treated by experienced foot and ankle surgeons. Significant bone loss can preclude revision total ankle replacement and obligate revision though a complex tibio-talo-calcaneal arthrodesis. A systematic review of the world literature reveals a nonunion rate of 24.2%. A weighted mean of modified American Orthopaedic Foot and Ankle Society Ankle and Hindfoot Scale demonstrated fair patient outcomes of 58.1 points on an 86-point scale (67.6 points on a 100-point scale). Complications were observed in 38 of 62 (62.3%) patients reviewed, with the most common complication being nonunion.

Gutter impingement after total ankle arthroplasty

BACKGROUND

Symptomatic gutter impingement after ankle arthroplasty has been reported with various designs. However, the incidence and origin of impingement have not been fully elucidated. Furthermore, the outcome of patients following gutter debridement has not been reported.

METHODS

A review of 489 total ankle replacements was performed to calculate the incidence of symptomatic gutter impingement in 4 different devices and between the presenting causes of arthritis. The incidence of gutter impingement was determined for patients with and without preemptive gutter resection at the time of implantation. The functional outcome of 30 of the 34 patients who had subsequent gutter debridement was determined with 3 different outcome instruments.

RESULTS

Symptomatic gutter disease occurred in 34 of 489 cases (7%) followed for a minimum of 1 year (range, 1-12 years). There was a 2% incidence of gutter disease in the 194 ankles that had prophylactic gutter resection at the time of implantation and a 7% incidence in the 295 ankles that did not have gutter resection at the time of implantation. When the ankle treated with an Agility (DePuy Orthopaedics, Inc, Warsaw, IN) device was excluded, there was a 2% and an 18% incidence of gutter disease in the 2 groups, respectively (P < .05). There was no difference in the incidence of gutter disease between the various implants and origins of ankle arthritis. Postoperative outcomes were favorable in the 27 patients who did not have another procedure after the initial gutter debridement. Seven patients (21%) required reoperation.

CONCLUSION

Prophylactic gutter resection should be considered at the time of implantation to reduce the incidence of postoperative symptoms. Although most patients had favorable outcomes following gutter debridement, there was a high reoperation rate.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

History of total ankle replacement

Attempts at ankle replacement have existed for at least 50 years. Time has essentially eliminated constrained, cemented, first-generation ankle replacements. Although some two-component, more anatomic, designs are still used with varying success, three-component "mobile bearing" ankle prostheses are winning the race of evolution. Not only have implants change over the years, but also the patients and surgeons. Surgeons specialize, improving their surgical outcomes and expanding the indications for total ankle replacement in technically demanding complex ankles. High-demand, younger patients, but also obese ones, are potential candidates for a total ankle replacement. This article provides a review of the history of total ankle replacement.