There is limited literature on the effects of socioeconomic factors on outcomes after total ankle arthroplasty (TAA). In the setting of hip or knee arthroplasty, patients of a lower socioeconomic status demonstrate poorer post-operative satisfaction, longer lengths of stay, and larger functional limitations. It is important to ascertain whether this phenomenon is present in ankle arthritis patients. This is the first study to address the weight of potential socioeconomic factors in affecting various socioeconomic classes, in terms of how they benefit from ankle arthroplasty. This is retrospective cohort study of 447 patients who underwent a TAA. Primary outcomes included pre-operative and final follow-up AAOS pain, AAOS disability, and SF-36 scores. We then used postal codes to determine median household income using Canadian 2015 census data. Incomes were divided into five groups based on equal amounts over the range of incomes. This method has been used to study medical conditions such as COPD and cardiac disease. These income groups were then compared for differences in outcome measures. Statistical analysis was done using unpaired t-test. A total of 447 patients were divided into quintiles by income. From lowest income to highest income, the groups had 54, 207, 86, 64, and 36 patients, respectively. The average time from surgery to final follow up was 85.6 months. Interestingly, we found that patients within the middle household income groups had significantly lower AAOS disability scores compared to the lowest income groups at final follow-up (26.41 vs 35.70, p=0.035). Furthermore, there was a trend towards middle income households and lower post-operative AAOS pain scores compared to the lowest income group (19.57 vs 26.65, p=0.063). There was also a trend toward poorer AAOS disability scores when comparing middle income groups to high income groups post-operatively (26.41 vs 32.27, p=0.058). Pre-operatively, patients within the middle-income group had more pain, compared to the lowest and the highest income groups. No significant differences in SF-36 scores were observed. There were no significant differences seen in middle income groups compared to the highest income group for AAOS pain post-operatively. There were no significant differences found in pre-operative AAOS disability score between income groups. Patients from middle income groups who have undergone TAA demonstrate poorer function and possibly more pain, compared to lower and higher income groups. This suggests that TAA is a viable option for lower socioeconomic groups and should not be a source of discouragement for surgeons. In this circumstance there is no real disparity between the rich and the poor. Further investigation is needed to explore reasons for diminished performance in middle class patients

Preoperative talar valgus deformity increases the technical difficulty of total ankle replacement (TAR) and is associated with an increased failure rate. Deformity of ≥15° has been reported to be a contraindication to arthroplasty. The goal of the present study was to determine whether the operative procedures and clinical outcomes of TAR for treatment of end-stage ankle arthritis were comparable for patients with preoperative talar valgus deformity of ≥15° as compared to those with <15°. We will describe the evolving surgical technique being utilized to tackle these challenging cases. Fifty ankles with preoperative coronal-plane tibiotalar valgus deformity of ≥15° “valgus” group) and 50 ankles with valgus deformity of <15° (“control” group) underwent TAR. The cohorts were similar with respect to demographics and components used. All TARs were performed by a single surgeon. The mean duration of clinical follow-up was 5.5 years (minimum two years). Preoperative and postoperative radiographic measurements of coronal-plane deformity, Ankle Osteoarthritis Scale (AOS) scores and Short Form (SF)-36 scores were prospectively recorded. All ancillary (intraoperative) and secondary procedures, complications and measurements were collected. The AOS pain and disability subscale scores decreased significantly in both groups. The improvement in AOS and SF-36 scores did not differ significantly between the groups at the time of the final follow-up. The valgus group underwent more ancillary procedures during the index surgery (80% vs 26%). Tibio-talar deformity improved significantly toward a normal weight-bearing axis in the valgus group. Secondary postoperative procedures were more common in the valgus group (36%) than the controls (20%). Overall, re-operation was not associated with poorer patient outcome scores. Metal component revision surgery occurred in seven patients (three valgus and four controls). These revisions included two deep infections (2%), one in each group, which were converted to hindfoot fusions. Therefore, 94% of the valgus group retained their original components at final follow-up. Thus far, this is the largest reported study that specifically evaluates TAR with significant preoperative valgus alignment, in addition to having the longest follow-up. Satisfactory midterm results were achieved in patients with valgus mal-alignment of ≥15°. The valgus cohort required more procedures during and after their TAR, as well as receiving more novel techniques to balance their TAR. Whilst longer term studies are needed, valgus coronal-plane alignment of ≥15° should not be considered an absolute contraindication to TAR if the associated deformities are addressed

Recent innovations in total ankle replacement (TAR) have led to improvements in implant survivorship, accuracy of component positioning and sizing, and patient outcomes. CT-generated pre-operative plans and cutting guides show promising results in terms of placement enhancement and reproducibility in clinical studies. The purpose of this study was to determine the accuracy of 1) implant sizes used and 2) alignment corrections obtained intraoperatively using the cutting guides provided, compared to what was predicted in the CT generated pre-operative plans. This is a retrospective study looking at 36 patients who underwent total ankle arthroplasty using a CT generated pre-operative planning system between July 2015 and December 2017. Personalized pre-operative planning data was obtained from the implant company. Two evaluators took measurements of the angle corrected using pre- and post-operative weight bearing ankle AP X-rays. All patients had a minimum three-month follow-up with weightbearing postoperative radiographs. The actual correction calculated from the radiographic assessment was compared with the predicted angles obtained from pre-operative plans. The predicted and predicted alternative component sizes and actual sizes used were also compared. If either a predicted or predicted alternative size was implanted, we considered it to be accurate. Average age for all patients was 64 years (range 40–83), with a body mass index of 28.2 ± 5.6. All surgeries were performed by two foot and ankle surgeons. The average total surgical time was 110 ± 23 minutes. Pre-operative alignment ranged from 36.7 degrees valgus to 20 degrees varus. Average predicted coronal alignment correction was 0.8 degrees varus ± 9.3 degrees (range, 18.2 degrees valgus to 29 degrees varus) and average correction obtained was 2.1 degrees valgus ± 11.1 degrees. Average post-op alignment was consistently within 5 degrees of neutral. There were no significant differences between the predicted alignments and the postoperative weightbearing alignments. The predicted tibia implant size was accurate in all cases. The predicted sizes were less accurate for talar implants and predicted the actual talar implant size used in 66% of cases. In all cases of predicted talar size mismatch, surgical plans predicted 1 implant size larger than used. Preliminary analyses of our data is comparable to previous studies looking at similar outcomes. However, our study had higher pre-operative deformities. Despite that, post-op alignments were consistently within 5 degress of neutral with no significant difference between the predicted and actual corrections. Tibial implant sizes are highly accurate while talar implant sizes had a trend of being one size smaller than predicted. Moreover, this effect seems to be more pronounced in the earlier cases likely reflective of increasing surgeon comfort with the implant with each subsequent case. These results confirm that pre-operative cutting guides are indeed helpful in intra-operative implant selection and positioning, however, there is still some room for innovation

Introduction:. Due to improvement in overall prosthesis designs and surgical methods, there have been increasing numbers of total ankle arthroplasty performed with encouraging intermediate results. While European registries have been able to perform long term follow-ups and analysis on total ankle arthroplasty patients, majority of the US studies have been based on experiences at a single institution. There is currently limited data on the recent trends of total ankle arthroplasty. The purpose of our study is to evaluate the in-patient demographics, complications and readmission rate in patients after total ankle arthroplasty at academic medical centers in United States. Patients & Methods:. We queried the University Healthsystems Consortium (UHC) administrative database from 2007 to 2011 for patients who underwent total ankle arthrolasty by ICD-9 procedure code 81.56. A descriptive analysis of demographics was performed, followed by a similar analysis of patient clinical benchmarks, including hospital length of stay, hospital direct cost, in-hospital mortality, and 30-day readmission rates. Results:. Our cohort consisted of 2,361 adult patients who underwent a total ankle arthroplasty at 95 different academic medical centers across the country during the specified time period. The annual surgical volume for individual surgeons who performed this procedure was 5 cases +/− 3. The cohort was comprised of 47% male and 53% female patients. The majority of the cohort 2,091 (88.5%) was white, 85 (3.6%) were black, 23 (1%) were Hispanic, and 162 (6.8%) other. The mean age of the cohort was 62 years old +/− 11. At least 70% of the cohort had one or more chronic medical conditions. The mean LOS for the cohort was 2.2 days +/− 1.26. The mean total direct cost for the hospital was $16,000 +/− 7,000 per case. 83% of the cohort had private insurance, 15% had Medicare, and 2% had Medicaid. In hospital mortality was less than 1% for the cohort during their index hospitalization. Inpatient complication rate include: DVT 2.3%, re-operation 0.7%, and infection 3.2%. There was a readmission rate of 2.6% within the first 30 days from the time of discharge. Discussion/Conclusion:. Total ankle arthroplasty in the United States is a relatively safe procedure with low overall complication rates including infection (3.2%), DVT (2.3%), and re-operation (0.7%). Length of stay after the procedure is around 2 days with a total direct hospital cost of $16,000 +/− $7,000 and 2.6% readmission rate (30 days). Majority of the patients were Caucasian and had private insurance

Introduction. Total Ankle replacement designs continue to evolve, and provide an alternative to ankle arthrodesis for patients with ankle arthritis. It has been our practice to offer total ankle replacement to selected patients with ankle arthritis. The purpose of this study was to analyse the short term results of our patients with the Mobility R Total Ankle Replacement (TAR) system. Methods. All patients who received TAR in our practice from 2004 to 2011 were reviewed. American Orthopaedic Foot and Ankle Scores AOFAS were assessed and compared both preoperatively and at time of follow-up. All complications both intra-operative and post-operatively were noted. Weight bearing X-rays were taken at follow-up, and implant alignment and the presence of lucencies were noted. Results. 21 patients were evaluated. All showed an improvement in AOFAS scores; however the improvement showed a wide variation. All patients showed an improvement in pain scores. Post-operative ankle stiffness, specifically dorsi-flexion, was problematic in several patients. Marked prolonged swelling was problematic for many patients. Conclusions. Total ankle replacement provides a good option for patients with ankle arthritis. Swelling and post-operative stiffness continue to be a problem, and should be explained to patients. MULTIPLE DISCLOSURES

Introduction. Total ankle replacement (TAR) is surgically complex; malalignment can arise due to surgical technique or failure to correct natural varus/valgus malalignment. Across joint replacement, malalignment has been associated with pain, component edge loading, increased wear and higher failure rates. Good component alignment is considered instrumental for long term TAR success. The conforming surface geometry of mobile bearing TARs leaves no freedom for coronal plane malalignment. The aim of this study was to investigate the biomechanical effect of coronal alignment on a mobile bearing TAR. Methods. Three TARs (Zenith, Corin Group) were tested under five coronal malalignment angles from 0–10° in a single station electromechanical knee simulator applying a typical ankle gait profile. As swing phase load is critical to TAR contact mechanics but will vary depending on the joint laxity. Swing loads of 100N, 300N and 500N were investigated. A positive control test with a swing load of 1000N was also studied, and was expected to eliminate the majority of lift off effects. Under each condition, the version was allowed to move freely while tests were performed, and the version profile under each alignment angle was recorded. Each test was carried out for 600 cycles in 25% bovine serum. Under the same loading conditions, but without lubrication, a Tekscan sensor recorded data from two cycles to assess the change in contact pressure and area at the five coronal angles. Results. Across the three TARs the effect of the swing phase load varied the biomechanics with a similar pattern. The high swing load of 1000N eliminates the majority of version while with 100N swing loads the TAR abducts for the length of the swing phase only realigning when the force increases, the extent dependent on the malalignment angle. At both 300N and 500N swing loads there is an oscillation apparent which changes the contact mechanics. The Tekscan results (Figure 1b) show changes in the contact area at three points in the load cycle; swing, the lower peak and the peak load (Figure 1a). With any degree of malalignment, component lift off is highly prevalent under lower swing phase loads of 100–300N. As the swing load is increased, this effect is only noticeable at greater malalignment angles. Discussion. The observed component lift off results in edge loading and peak pressures occurring at the insert edges. When the insert is 10 degrees coronally malaligned and the insert is brought fully into contact, the peak pressure reaches 16–18MPa, a pressure similar to the yield stress of polyethylene. The high contact pressures will likely elevate the wear and may increase the potential for polyethylene failure. Conclusion. Biomechanical testing has shown the malalignment of a total ankle replacement combined with the joint tension may change the contact mechanics and potentially increase wear. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Restoration of ankle alignment is thought to be critical in total ankle arthroplasty (TAA) outcomes, but previous research is primarily focused on coronal alignment. The purpose of this study was to investigate the sagittal alignment of the talar component. The talar component inclination, measured by the previously-described gamma angle, was hypothesized to be predictive of TAA outcomes. A retrospective review of the Canadian Orthopaedic Foot and Ankle Society (COFAS) database of ankle arthritis was performed on all TAA cases at a single center over a 11-year period utilizing one of two modern implant designs. Cases without postoperative x-rays taken between 6 and 12 weeks were excluded. The gamma angle was measured by two independent orthopaedic surgeons twice each and standard descriptive statistics was done in addition to a survival analysis. The postoperative gamma angles were analyzed against several definitions of TAA failure and patient-reported outcome measures from the COFAS database by an expert biostatistician. 109 TAA cases satisfied inclusion and exclusion criteria. An elevated postoperative gamma angle higher than 22 degrees was associated with talar component subsidence, defined as a change in gamma angle of 5 degrees or more between postoperative and last available followup radiographs. This finding was true when adjusting for age, gender, body mass index (BMI), and inflammatory arthritis status. All measured angles were found to have good inter- and intraobserver reliability. Surgeons should take care to not excessively dorsiflex the talar cuts during TAA surgery. The gamma angle is a simple and reliable radiographic measurement to predict long-term outcomes of TAA and can help surgeons counsel their patients postoperatively

Background. Total ankle arthrpoplasty (TAA) was performed frequently for ankle deformity caused by rheumatoid arthritis (RA) and osteoarthritis (OA). TAA has some advantages over ankle arthrodesis in range of motion (ROM). However, loosening and sinking of implant have been reported with several prostheses, especially constrained designs. Recently, we have performed mobile bearing TAA and report short term results of this prosthesis followed average 3 years. Method. 20 total ankle prostheses were implanted in patients with RA (n=14) or OA (n=6) in 19 patients (5 male and 14 female, one bilateral), between 2005 and 2009. We used FINE total ankle arthroplasty that is mobile bearing system (Nakashima Medical Co., Ltd, Okayama, Japan). All patients were assessed for American Orthopaedic Foot and Ankle Society (AOFAS) score, ROM in plantar flexion and dorsiflexion at the point of pre-operation and final follow-up. We evaluated radiolucent line, sinking, and alignment of prostheses at final follow-up. Results. At the operation, patients were, on average, 64.1 years old. The mean follow-up period was 34.0 (6∼55) months. We found excellent satisfaction and a significant improvement of AOFAS score. Plantar flexion and dorsiflexion also improved compared with the preoperative state, but not significantly (table 1). At final follow-up, five ankles (25%) showed radiolucent line around the components or sinking of prostheses. Three ankles (15%) was performed reoperation, due to early infection, progressive medial OA change by sinking, and loosening of the talus component. Discussion. Radiolucent line around the components or sinking of prostheses occurred at high frequency (25%). But, only two ankles (10%) were had to reoperation, cause by pain. We take account of the fact that the symptom was lack in spite of radiological changes. Good clinical results can be achieved with FINE total ankle arthroplasty system. However, this series was short term of follow-up. We need to evaluate mid- and long- clinical results. Mobile bearing total ankle arthroplasty is a treatment option for RA and OA

Introduction. Degenerative, inflammatory, and posttraumatic arthritis of the ankle are the primary indications for total ankle arthroplasty. Ankle arthrodesis has long been the “gold standard” for the surgical treatment. Total Ankle Arthroplasty. implant survivorship has been reported to range from 70% to 98% at three to six years. The combination of younger age and hindfoot arthrodesis or osteoarthritis may lead to a relative increase in failure rates after TAA. Intraoperative complication include malaligment, fracture and tendon Postoperative complications include syndesmotic nonunion, wound problems, infections and component instability and lysis. After TAA few difficulties mainly due to poor Talar and Tibial bone stock. It is difficult to stabilize the fusion and usually there is shortening after removal of the implant. Also there is a need for massive bone graft-allograft or autograft. In cases when there is significant bone loss there is a need for stable reconstruction and stabilization of the hindfoot. Bone grafting with structural bone graft may collapse and it has to be stabilized with screws or nail. Methods. We developed technique which included distraction of the fusion area and inserting a Titanium cylindrical spinal cage filled with bone graft. Than guide wire was inserted in through the cage under fluoroscopy and a compression screw was introduced causing compression of the fusion area against the cage gaining stabilization of the fusion area. Results. By 6 months all the patients were fused and could walk full weight bearing with no pain. Discussion and Conclusions. Spinal cages are widely used in spine fusions in order to achieve stable spacer. Usually it has to be stabilized using posterior fusion stabilizing system. By performing distraction of the fusion area by spinal cage used as spacer and compression at the same time using compression screw we achieved primary good stability with minimal shortening

Power production in the terminal stance phase is essential for propelling the body forward during walking and is generated primarily by ankle plantarflexion. Osteoarthritis (OA) of the ankle restricts joint range of motion and is expected to reduce power production at that ankle. This loss of power may be compensated for by unaffected joints on both the ipsilateral and contralateral limbs resulting in overloading of the asymptomatic joints. Total ankle arthroplasty (TAA) has been shown to reduce pain and has the potential to restore range of motion and therefore increase ankle joint power, which could reduce overloading of the unaffected joints and increase walking speed. The purpose of this study was to test the hypothesis that ankle OA causes a loss of power in the affected ankle, compensatory power changes in unaffected lower limb joints, and that TAA will increase ankle power in the repaired ankle and reduce compensatory changes in other joints. One hundred and eighty-three patients (86 men, 97 women with average ages 64.1 and 62.4 years respectively) requiring surgical intervention for ankle OA were prospectively enrolled. Implant selection of either a fixed (INBONE or Salto Talaris) or mobile (STAR) bearing implant was based on surgeon preference. Three-dimensional kinematics and kinetics were collected prior to surgery and one year post-operatively during self-selected speed level walking using an eight-camera motion capture system and a series of force platforms. Subject walking speed and lower extremity joint power during the last third of stance at the ankle, knee, and hip were calculated bilaterally and compared before and after surgical intervention across the entire group and by implant type (fixed vs. mobile), and gender using a series of ANOVAs (JMP SAS, Cary, NC), with statistical significance defined as p < 0 .05. There were no gender differences in age, walking speed, or joint power. All patients increased walking as a result of surgery (0.87 m/s±0.26 prior to surgery and 1.13 m/s±0.24 after surgery, p < 0 .001) and increased total limb power. Normalized to total power (which accounts for changes in speed and distribution of power production across joints), prior to surgery the affected ankle contributed 19%±10% of total power while the unaffected ankle contributed 42%±12% (P < 0 .001). After surgery, the affected ankle increased to 25%±9% of total power and the unaffected ankle decreased to 38%±9% of total (P < 0.001). Other joints showed no significant power changes following surgery. Fixed bearing implants provide greater surgical ankle power improvement (61% versus 29% increase, p < 0 .002). Much of that change was due to the fact that those that received fixed-bearing implants had significantly lower walking speed and power before surgery. Ankle OA reduced ankle power production, which was partially compensated for by the unaffected ankle. TAA increases walking speed and power at the affected ankle while lowering power production on the unaffected side. The modifications in power production could lead to increased physical activity and reduced overloading of asymptomatic joints

Purpose. The purpose of this study was to assess the biomechanical stability of the a total ankle arthroplasty system using longitudinal migration (LM) and inducible displacement (ID) measures. This study is the first study of its kind to assess total ankle arthroplasty (TAA) implant micromotion using model-based radiostereometric analysis (MBRSA). Method. Twenty patients underwent TAA that implanted the Mobility(TM) (DePuy, Warsaw IN). The mean (SD) age was 60.4 (12.5) and BMI was 29.1 (2.8) kg/m. 2. One surgeon performed all surgeries. All patients included in this study had given informed consent. Capital Health Research Ethics Board had approved this study. Uniplanar medial-lateral RSA X-ray exams were taken postop (double exam), at six wk, three mth, six mth, one yr and two yr followup times using a supine, unloaded position. Standing medial-lateral exams were taken at three mth, six mth, one yr and two yr followup intervals. LM and ID micromotions were assessed using Model-based RSA 3.2 software (Medis specials, Leiden, The Netherlands). Implant micromotions (x, y, z, Rx, Ry, Rz, MTPM) were determined and assessed for each subject using model-based pose estimation, and the implant-based coordinate system. The Elementary Geometric Shapes module from the Model-based RSA 3.2 software was used to assess the micromotion of the tibial component spherical tip due to implant symmetry. Results. The median (range) maximum total point motion (MTPM) for the implants at 2 year followup were 1.23 mm (0.39–1.95 mm) for the talar implant and 0.96 mm (0.17–2.28 mm) for the spherical tip of the tibia implant. Generally for each subject and implant component, the slopes of the migration curves decreased over time. The talar and tibial implants mean LM showed initial subsidence in the y-direction (migration into the bone) followed by stabilization patterns at one year followup. The median (range) of two year MTPM ID for the talar component was 0.39 (0.27–1.06) mm. At the one year and two year followup times the ID were almost all below the detection limit of 0.85 mm. The highest measured displacement for any one talar component at either of these times was 1.06 mm. Hence, the implant was displaced at least 0.21 mm under loading. The median (range) of one year and two year MTPM ID for the tibial component spherical tip was 0.08 (0.03–0.19) mm. The tibial component spherical tip demonstrates no ID in terms of MTPM greater than the 0.22 mm detection limit. Conclusion. The implant subsides directly into the bone in the line of primary loading during standing or walking. For most of the patients the two year LM for the Mobility(TM) demonstrates a typical subsidence-stabilization behaviour seen in many RSA studies of orthopaedic implants. Based on the results of this study the Mobility(TM) components show no measurable ID. This is the first study of its kind internationally for total ankle arthroplasty and offers novel insight into the need for prosthetic design change

Background. Total ankle arthroplasty (TAA) is an alternative to ankle arthrodesis, replacing the degenerated joint with a mechanical motion-preserving alternative. Implant loosening remains a primary cause of TAA revision, and has been associated with wear-mediated osteolysis. Differing implant designs have a major influence on the wear performance of joint replacements. Providing a range of implant sizes allows surgeons a greater intra-operative choice for varying patient anatomy and potential to minimise wear. Minimal pre-clinical testing exists in the literature that investigates the effect of implant size on the wear behaviour. The aim of this study therefore was to investigate the effect of two different implant sizes on the wear performance of a TAA. Materials & Methods. Six ‘medium’ and six ‘extra small’ BOX® (MatOrtho Ltd, UK) TAA implants, of the same conceptual design and polyethylene insert thickness, were tested in a modified 6 station pneumatic knee simulator. 5 million cycles (Mc) of wear simulation were completed for each implant size, under kinematics aiming to replicate an ankle gait cycle (Figure 1) [1]. The simulator used had six degrees of freedom, of which four were controlled. The maximum axial load was 3150N, equivalent to 4.5 times body weight of a 70kg individual. The flexion profile ranged from −15° plantarflexion to 15° dorsiflexion. Rotation about the tibial component ranged from −2.3° of internal rotation to 8° external rotation, and anterior/posterior (AP) displacement ranged from 3.1 mm anterior to −0.9 mm posterior displacement. The lubricant used was 25% bovine serum supplemented with 0.04% sodium azide to prevent bacterial degradation. The wear of the TAA polyethylene inserts were determined gravimetrically after each Mc, with unloaded soak controls used to compensate for the uptake of moisture by the polyethylene. Results. There were no significant differences (P = 0.872) in the mean wear rates (± 95% confidence limits) between the medium (11.00 ± 3.06 mm3/Mc) and extra small (10.64 ± 4.61 mm3/Mc) implant sizes (Figure 2). An observation of insert surfaces showed clear signs of abrasive wear and burnishing (Figure 3). There was evidence of polyethylene transfer and scratching on the tibial components, while talar components displayed fine linear scratching in similar directions for both implant sizes. Conclusions. The wear rates of both implant sizes are comparable to the wear rate (13.30 ± 2.50 mm3/Mc) of a previous wear study, which was conducted on ‘medium-sized’ Corin Zenith TAAs, under the same simulator conditions for 2 Mc [1]. The wear rates for both implant sizes are substantially lower than the wear of four ‘small-sized’ BOX® ankles (18.60 ± 12.80 mm3/Mc) for 2Mc [2]. The considerable difference in wear rates may be due to the lower forces, higher AP and deionised water as the test lubricant [2], which does not replicate the features of the natural synovial fluid and produce tribological artefact. The results from this study suggest that under the same kinematic and kinetic conditions, the wear rates are unaffected by a change in TAA implant size

Aim. This controlled study uses gait analysis to evaluate patients' pre- and post-ankle arthroplasty, post-ankle arthrodesis and compares the results with a healthy control group to assess whether these theoretical benefits are borne out in clinical practice. Method. Five patient groups (arthrodesis, arthroses, arthroplasty after 6 and 12 months and control) each consisting of 12 patients were analysed in our gait laboratory and the following parameters obtained at two different walking speeds: velocity, cadence, step length, stride length, the timing of toe off and the duration of stance phase. In addition, the ground reaction force during the whole gait cycle was recorded, as well as the range of movement of the knee and of the foot in relation to the tibia in walking and functional tests. Results. Subjects who had undergone arthrodesis were able to go faster with a longer step length on the affected side than their counterparts with an ankle prosthesis. However, this gain seemed to be at the expense of a symmetrical gait pattern and increased knee movement. Ankle prostheses also produced a stance phase and ground reaction force that was closer to the control group in duration and timing and also a more symmetrical timing of toe off. Discussion. Overall, our data supports the clinical observation that the gait pattern after total ankle replacement is more symmetrical with a less pronounced limp than in ankle arthrodesis. It is hoped that this will lead to decreased strain on neighbouring joints; however, the long term benefit of this is not yet established. It is not yet clear whether the long term implant survivorship of total ankle replacement is of sufficient duration to justify this unproven benefit

We aimed to review the outcome of Agility total ankle replacements carried out in our institution between 2002 and 2006. Follow-up consisted of clinical and radiological review pre-operatively, then at 6 weeks, 6 and 12 months, and annually until 10 years post op. Clinical review included the American Orthopaedic Foot and Ankle Score, satisfaction and pain scores. Case notes were reviewed to determine intra and post-operative complications. 30 arthroplasties were performed in 30 consecutive patients. Pre-operative diagnosis was rheumatoid arthritis(16), primary osteoarthritis(12) and post-traumatic osteoarthritis(2). After a mean follow up of 6.2 years (1.4–10.1), 4 patients had died, and 22 out of the remaining 24 were available for follow-up. Intra operative complications included lateral malleoli fracture(3) and superficial peroneal nerve injury(2). Post operative complications included 1 early death, but this was not related to the surgical procedure. Two patients developed deep infections of the prosthesis. One underwent removal of the implant; the other is on long term oral antibiotic therapy. One patient had delayed union of the syndesmosis and six patients had non-union. On clinical assessment, patients' AOFAS scores improved from mean 40.4 pre-op to 83.5 post-op (p< 0.001). Radiological assessment of the tibial component revealed 25 (93%) patients had lucency in at least one zone in the AP radiograph. We found a relatively high level of re-surgery and complications following Agility total ankle replacement. A 7% revision rate is much higher than would be tolerated in knee or hip arthroplasty, but compares favourably to other studies of TAR. Despite radiological features which suggest loosening, the high rate of re-surgery and complications; patients are generally satisfied with the procedure, reporting lower levels of pain and improved function. Overall we feel that the Agility ankle is an acceptable alternative to ankle arthrodesis, however patients need to be warned of the risk of re-surgery

Purpose. The failure rate of total ankle arthroplasty (TAA) in rheumatoid patients may be higher than in osteoarthritis patients due to the medications used to treat rheumatoid arthritis and the comorbidities associated with this disease. The purpose of this study was to prospectively look at the intermediate-term outcomes of TAA in patients with rheumatoid arthritis and to compare the results to a matched cohort of patients with ankle osteoarthritis undergoing TAA. Method. This study is a prospective, multicentre comparison study of patients two to eight years post-TAA. A cohort of 57 patients with rheumatoid arthritis was identified from the prospective national database of TAAs (RA group). Matched controls were identified in the database using age, type of prosthesis, and follow-up time as matching criteria (OA group). The following data was collected: demographic information, previous and additional surgeries at the time of TAA and major and minor complications including revisions. Generic and disease specific, validated outcome scores collected include the Short-Form 36 (SF36) and Ankle Osteoarthritis Score (AOS). Results. Each group consisted of 42 female and 15 male patients with an average follow-up of four years. The two groups were similar with an average age of 59.55 years (33–82) in the RA group and 58.13 years (36–85) in the osteoarthritis group and an average BMI of 25.77 kg/m2 in the RA group and 27.70 kg/m2 in the OA group. Preoperative AOS scores were similar in both groups: 64.42 for pain and 72.59 for disability in the RA group and 58.39 for pain and 72.37 for disability in the OA group. There was a significant improvement at latest follow-up: 16.64 for pain and 27.03 for disability in the RA group and 11.75 for pain and 22.66 for disability in the OA group. The OA group had a greater improvement in the SF-36 physical component score (29.97 to 41.29 versus 26.88 to 34.82 in the RA group) whereas the RA group had a greater improvement in the mental component score (49.71 to 56.90 versus 48.99 to 52.02 in the OA group). There was a higher rate of additional surgeries, predominantly hindfoot fusions, in the RA group than the OA group (33 versus 13). Revision rates were similar between the two groups with two revisions in the RA group and three in the OA group. There were no major wound complications in the OA group and two in the RA group. Conclusion. Total ankle arthroplasty is a good option for patients with rheumatoid arthritis. A greater number of additional surgeries were required to balance the foot and support the ankle replacement in the rheumatoid patients than in the osteoarthritis patients. Both groups showed similar improvement in a generic quality of life outcome measure (SF36) and a disease specific functional outcome measure (AOS). Revision rates were similar between the groups; however, the patients with rheumatoid arthritis had a higher rate of wound complications

Purpose. To investigate the effect of obesity on functional outcome following total ankle arthroplasty. Method. We identified 43 obese patients (46 ankles) (BMI > 30kg/m2), using a prospectively collected database of total ankle arthroplasties. Inclusion criteria included: (a) Post-traumatic or inflammatory arthritis; (b) Minimum two-year follow-up, (c) Coronal plane deformity less than 10 degrees. Exclusion criteria: (a) Co-morbidity affecting physical function; (b) Recent total joint arthroplasty. American Orthopaedic Foot and Ankle Society (AOFAS), Ankle Osteoarthritis Scale (AOS) and SF-36 questionnaires were used preoperatively and at latest follow-up. Revision was defined as any intervention requiring replacement of part or whole of the prosthesis. A control group of non-obese individuals (BMI 18.5–29.9kg/m2) was devised matching for age within 10 years, gender, diagnosis, implant and length of follow-up (within 1 year). From the original group of 46 ankles, we matched 28 ankles, thereby constructing two groups for comparison (matched obesity and control). Results. From the original obesity group (n=46, mean BMI 34.7, age 65.1 years and follow-up 3.5 years), four patients were lost to follow-up. There were 10 revisions (21.7%) including five for liner exchange, four full component and one revision to fusion. Statistically significant (p<0.001) improvements were detected with all outcome measures (AOFAS, AOS and SF-36). In the matched obesity and control groups we used 11 STAR, 11 Mobility and six Hintegra implants. Delayed wound healing affected one patient in each group. In the matched obesity group (mean BMI 35), there were six revisions (three liner exchange, three full component) (21.4%), at a mean of 3.2 years. One patient was lost to follow-up (known to be revised). Statistically significant improvements were noted with all outcome measures. In the control group (mean BMI 26.1), there were three revisions (two liner exchange and one full component) (10.7%), at a mean of 2.3 years. All patients were followed-up. Statistically significant improvements were associated with all outcome measures except the mental component summary of the SF-36 (52.2 to 54, p=0.37). The same score pre-operatively was lower in the matched obesity group (45 vs. 52.2, p=0.193). Overall, no difference was found in mean outcome score improvement between groups. In the matched obesity group, the mean pre-operative AOS pain score was higher (58.8 vs. 46.5) (p=0.016), as was the preoperative AOS disability score (68.4 vs. 58.5) (p=0.082). The mean post-operative AOS pain and disability scores were also higher, although not reaching significance (p=0.096 and p=0.241 respectively). Conclusion. Obesity is associated with greater functional and psychological preoperative burden, although the overall improvement in functional outcome is comparable to non-obese matched controls. Obese patients can expect a significantly higher revision rate (21.4% vs 10.7%) within five years of surgery

Introduction and aims. Recently many implants for ankle arthroplasty have been developed around the world, and especially some mobile bearing, three-component implants have good results. Nevertheless, at our institution fixed two-component, semi-constrained alumina ceramic total ankle arthroplasty (TAA) with TNK Ankle had been performed since 1991 and led to improved outcomes. We report clinical results and in vivo kinematic analyses for TNK Ankle. Method. Between 1991 and 2006, total ankle arthroplasties with TNK Ankle were performed with 102 patients (106 ankles) with osteoarthritis at our institution. There were 91 women and 11 men. The mean age was 69 years and mean follow-up was 5.4 years. These cases were evaluated clinically and radiographically. Besides in vivo kinematics, in TNK Ankle was analysed using 3D-2D model registration technique with fluoroscopic images. Between 2007 and 2008, prospectively ten TAA cases examined with fluoroscopy at postoperative one year. Results. In clinical results, excellent were 48 cases, good were 31 cases, fair were 10 cases, poor were nine cases, and death and loss to follow-up were 10 cases. Reoperations are performed on eight cases, one was arthrodesis, seven were talar component revision or talar revision with ceramic whole talus prosthesis. TNK Ankle have the rough surfaces by beadworks, and added surface treatment with hydroxyapatite granules, calcium phosphate paste or tissue engineered mesenchymal cells. Recently, only talar components were fixed with bone cement. Loosening has been more frequent in talar than tibial, whereas no reoperation was on cemented talar component cases. According to 3D-2D model registration, both components rotated a little each other and the contact region between both components variously sifted during weight bearing flexion of ankle. It was supposed that replaced position and angle of components concerned with the contact region. Conclusions. TAA with TNK Ankle have led to better results with improvement for surface treatments. Kinematics of ankle prostheses was derived by 3D-2D model registration, more appropriate position and angle to replace

Introduction. Ankle arthrodesis is a common treatment for destroyed ankle arthrosis with sacrificing the range of motion. On the other hand, total ankle arthroplasty (TAA) is an operation that should develop as a method keeping or improving range of motion (ROM); however, loosening and sinking of the implant have been reported in especially constrained designs of the implant. The concept of FINE TAA is the mobile bearing system (Nakashima Medical Co., Ltd, Okayama Japan) that can reduce stress concentration to implants. The purpose of this study is to evaluate the short-term results of FINE TAA. Objectives and Methods. We performed FINE TAA for osteoarthritis (OA) (2 ankles of 2 patients) and rheumatoid arthritis (RA) (4 ankles of 3 patients). All patients were female. The mean age of the patients was 71.4 years old at the operation. The mean follow-up period was 32.6 (range, 18–55) months. All patients were assessed for Japan Orthopedic Association (JOA) score and ROM in plantar flexion and dorsiflexion at the point of pre-operation and final follow-up. We evaluated radiolucent line, subsidence, and alignment of implants at the latest follow-up. Results. JOA score improved from 34.8 to 72.2 on average. ROM improved from 4.0 ± 5.5 º to 7.0 ± 4.5 º on average in plantar flexion and from 21.0 ± 17.0 º to 31.0 ± 16.0 º in dorsiflexion. One case underwent an ankle arthrodesis because of the implant loosening. This failed case was very obese (70 kg of body weight, 31.0 of Body Mass Index) and her activity was relatively high. One ankle showed radiolucent line around the components with no symptoms. The alignment of implants was slightly varus and anteversion (the mean values of alpha angle was 88.0 ± 1.2º, beta angle was 84.0 ± 9.2º, and gamma angle was 2.1 ± 0.2º). Discussion. The ankle joint is highly loaded up to five times body weight on small surface of contact area during walking. Therefore, the poor results have been published after TAA with using fixed-bearing 2-component prostheses compared to ankle arthrodesis. On the other hand, FINE TAA was designed as 3-component mobile bearing system that can reduce stress concentration compared to conventional TAA. We experienced implant failure in one obese case but short-term results of other cases were acceptable. Good clinical results can be expected with FINE TAA except for the obese case. We should pay careful attention to the surgical indication. Conclusion. Our short term results of FINE TAA were acceptable except for one obese case. We should evaluate further mid- and long- clinical results

Purpose. To prospectively assess the safety, efficacy and patient satisfaction of a standardised perioperative anesthetic and pain management protocol for outpatient Total Ankle Arthroplasty. Method. Starting February 2008 we chose to enrol 50 consecutive patients undergoing Total Ankle Arthroplasty in this study. All patients were assesed and treated by a single Anesthesiologist and Orthopedic surgeon. All patients received preoperative dosing of Celebrex, Oxycontin and Gabapentin. Anesthesia consisted of a popliteal regional block and a spinal anesthetic. Patients were discharged home when they were stable with adequate pain control and able to ambulate with crutches or a walker. All patients were contacted by telephone by the treating Anesthesiologist to assess for pain control, complications and satisfaction on the night of surgery and for the next two days. Patients were also given contact numbers to call the Anesthesiologist for any concerns outside of these times. All patients were assessed by the treating Orthopedic surgeon at two and six weeks post surgery with data collected regarding wound complications, infection, deep venous thrombosis and overall patient satisfaction. Results. All 50 consecutive patients underwent successful regional and spinal anesthesia. All patients were stable for discharge the same day as the surgery. One patient experienced nausea in the Recovery Room but was treated with standard antinausea medication and was subsequently discharged home. Forty three patients reported pain scores of less than 3/10 throughout the post operative phase. Four patients experienced mild pain (3/10) and three patients reported moderate pain level (5/10). All seven patients were treated with analgesic dose titration and/or education regarding the need to take all medications prescribed at the proper time intervals. None of the patients required further intervention or readmission for either pain control or complications of anesthesia. All patients were reviewed by the treating Orthopedic surgeon at two and six weeks postoperatively. There were no early surgical complications and all wounds healed without difficulty or sepsis. All patients admitted to being satisfied or highly satisfied with their surgical experience and post operative pain management. Conclusion. Total Ankle Arthroplasty can be performed safely on an outpatient basis with excellent pain control and a high level of patient satisfaction. We now utilize regional anesthesia and the multimodal pre- and post-operative pain management protocol described for all complex foot and ankle surgery. This has allowed for greater throughput of operative cases and significant cost savings for our Institution

Purpose. The goal of Total Ankle Arthroplasty (TAA) is to relieve pain and restore healthy function of the intact ankle. Restoring intact ankle kinematics is an important step in restoring normal function to the joint. Previous robotic laxity testing and functional activity simulation showed the intact and implanted motion of the tibia relative to the calcaneus is similar. However there is limited data on the tibiotalar joint in either the intact or implanted state. This current study compares modern anatomically designed TAA to intact tibiotalar motion. Method. A robotic testing system including a 6 DOF load cell (AMTI, Waltham, MA) was used to evaluate a simulated functional activity before and after implantation of a modern anatomically designed TAA (Figure 1). An experienced foot and ankle surgeon performed TAA on five fresh-frozen cadaveric specimens. The specimen tibia and fibula were potted and affixed to the robot arm (KUKA Robotics Inc., Augsburg, Germany) while the calcaneus was secured to a fixed pedestal (Figure 1). Passive reflective motion capture arrays were fixed to the tibia and talus and a portable coordinate measuring machine (Hexagon Metrology Group, Stockholm, Sweden) established the location of the markers relative to anatomical landmarks palpated on the tibia. A four camera motion capture system (The Motion Monitor, Innovative Sports Training, Chicago, IL) recorded the movement of the tibia and talus. The tibia was rotated from 30 degrees plantar flexion to 15 degrees dorsiflexion to simulate motions during the stance phase of gait. At each flexion angle the robot found the orientation which zeroed all forces and torques except compressive force, which was either 44N or 200N. Results. Preliminary data indicates the tibiotalar motion of the TAA is similar to the intact ankle. The pattern and magnitude of tibiotalar translations and rotations are similar between the intact and implanted states for both 44N and 200N compressive loads (Figure 2). The most variation occurs with internal-external rotation. Increased translation especially in the anterior-posterior directions was observed in plantarflexion while the mediolateral translation remained relatively centered moving less than a millimeter. The intact talus with respect to the calcaneus had less than 3 degrees of rotation over the whole arc of ankle flexion (Figure 3). The angular motion of the implanted talus was similar in pattern to the intact talus, however there were offsets in all three angular directions which changed depending on the loading (Figure 3). This indicates that most of the motion that occurs between the intact tibial calcaneal complex occurs in the tibiotalar joint. Conclusion. Although more investigation is required, this study adds to the limited available tibiotalar kinematic data. This current study suggests the anatomical TAA design allows the tibiotalar joint to behave in similar way to the intact tibiotalar joint. Restoring intact kinematics is an important step in restoring normal function to the joint. For figures/tables, please contact authors directly.