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

Introduction. Total ankle arthroplasty is increasingly used as an alternative to arthrodesis to treat advanced ankle arthritis. In an attempt to assess the survivorship and patient outcome as well as peri- and postoperative complications and possible risk factors, we retrospectively analyzed the demographics, clinical outcome and radiographic characteristics of 100 ankle prostheses (97 patients). Patients and methods. Between 3/2005 and 5/2010 114 S.T.A.R. Prostheses were implanted by one surgeon at our institution. Indication for TAA was primary and secondary osteoarthritis, 81 cases were posttraumatic. From the 53 female and 44 male patients the mean age was 63 and the mean BMI was 28,4. 11 patients had been smoking for longer than 12 years, 29 patients either had a history of diabetes, peripheral vascular or cardiovascular disease or varicosis. All operations were performed with a tourniquet, using a standard anterior midline incision. All patients received the same postoperative rehabilitation and follow up program. Postoperative evaluation included the AOFA Score and clinical radiographic follow ups 6 weeks after surgery and yearly thereafter. Additional procedures during surgery included lengthening of the Achilles tendon for 12 patients and fusion of the subtalar ankle for 5 patients. Results. The average follow up was 36 months. The preoperative AOFA Score of 36.87 (22–58) increased to 75.99 postoperative. 87 cases reported a better life quality and 82 cases would go for surgery again. 27 ankles incurred complications after primary surgery. 21 prostheses had to go for revision surgery. Most complications were due to aseptic loosening/ implant failure. Other complications include arthrofibrosis and impingement as well as delayed wound healing and deep infection. Four patients had to be revised to an athrodesis. Conclusion. Our study shows a high satisfaction rate after total ankle replacement and clear pain relief which is the primary indication for ankle arthroplasty. Patients with a body mass Index higher than 30 as well as patients with a history of diabetes or peripheral vascular disease and smokers showed a higher rate of complications. Although these are encouraging results, the rate of complications should be discussed with patients. Compared with ankle fusion, the rates of complications seem to be comparable

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 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