Total ankle replacements: an overview

Outcomes of Total Ankle Replacement

Total ankle replacement (TAR) is an effective operative treatment of end-stage ankle osteoarthritis (OA) in the appropriate patient, conferring improved kinematic function, decreased stress across adjacent joints, and offering equivalent pain relief in comparison to ankle arthrodesis (AA). It is important to consider patient age, weight, coronal tibiotalar deformity, joint line height, and adjacent joint OA to maximize clinical and patient outcomes. Both mobile-bearing and fixed-bearing implants have demonstrated favorable clinical outcomes, marked improvement in patient-reported outcomes, and good survivorship; however, implant survivorship decreases with longer term follow-up, necessitating constant improvement of primary and revision TAR options.

Ankle and Foot Arthroplasty and Prosthesis: A Review on the Current and Upcoming State of Designs and Manufacturing

The foot and ankle serve vital roles in weight bearing, balance, and flexibility but are susceptible to many diverse ailments, making treatment difficult. More commonly, Total Ankle Arthroplasty (TAA) and Total Talus Replacement (TTR) are used for patients with ankle degeneration and avascular necrosis of the talus, respectively. Ankle prosthesis and orthosis are also indicated for use with lower limb extremity amputations or locomotor disability, leading to the development of powered exoskeletons. However, patient outcomes remain suboptimal, commonly due to the misfitting of implants to the patient-specific anatomy. Additive manufacturing (AM) is being used to create customized, patient-specific implants and porous implant cages that provide structural support while allowing for increased bony ingrowth and to develop customized, lightweight exoskeletons with multifunctional actuators. AM implants and devices have shown success in preserving stability and mobility of the joint and achieving fast recovery, as well as significant improvements in gait rehabilitation, gait assistance, and strength for patients. This review of the literature highlights various devices and technologies currently used for foot and ankle prosthesis and orthosis with deep insight into improvements from historical technologies, manufacturing methods, and future developments in the biomedical space.

Two-year outcomes of MOBILITY Total Ankle Replacement

BACKGROUND

There is little literature on patient-reported outcomes following total ankle replacement in patients with osteoarthritis, posttraumatic osteoarthritis, and rheumatoid arthritis. We compared the differences in demographic data and clinical and patient-reported outcomes among patients with those types of arthritis who underwent total ankle replacement performed with use of the MOBILITY Total Ankle System.

METHODS

Patients were divided into three groups based on the preoperative diagnosis of type of arthritis. We analyzed patient demographic data, American Orthopaedic Foot & Ankle Society (AOFAS) scores, and patient-reported outcomes as measured with use of the Foot and Ankle Outcome Score (FAOS), the 36-item Short-Form (SF-36) Health Survey, and patient-satisfaction scores, collected preoperatively and at one and two years postoperatively.

RESULTS

The study included 106 consecutive patients who underwent total ankle replacement between March 2006 and December 2009. The posttraumatic osteoarthritis group, which had twenty-eight patients, was significantly younger (mean age, 54.8 yrs; p < 0.05) than the other groups; the rheumatoid arthritis group, which had twenty-two patients, had a significantly lower mean body mass index (24.5 kg/m(2); p < 0.05); and the osteoarthritis group, which had fifty-six patients, had a higher proportion of males (41 males; p < 0.05). The posttraumatic osteoarthritis group reported better scores for two of the eight domains of the SF-36 preoperatively. At one year postoperatively, the posttraumatic osteoarthritis group and the rheumatoid arthritis group had better FAOS results regarding pain than those of the osteoarthritis group, and the posttraumatic osteoarthritis group also reported better scores for the general health domain of the SF-36. At two years, the posttraumatic group continued to show significantly higher scores for the general health domain of the SF-36. There was no significant difference between the groups in terms of the AOFAS scores, other FAOS results, or the patient-satisfaction scores at one and two years postoperatively.

CONCLUSIONS

Our findings suggest that early outcomes after total ankle replacement for patients with posttraumatic osteoarthritis are comparable with those for patients with osteoarthritis and rheumatoid arthritis.

Long-term follow-up of mobile-bearing total ankle replacement in patients with inflammatory joint disease

Little is known about the long-term outcome of mobile-bearing total ankle replacement (TAR) in the treatment of end-stage arthritis of the ankle, and in particular for patients with inflammatory joint disease. The aim of this study was to assess the minimum ten-year outcome of TAR in this group of patients. We prospectively followed 76 patients (93 TARs) who underwent surgery between 1988 and 1999. No patients were lost to follow-up. At latest follow-up at a mean of 14.8 years (10.7 to 22.8), 30 patients (39 TARs) had died and the original TAR remained in situ in 28 patients (31 TARs). The cumulative incidence of failure at 15 years was 20% (95% confidence interval (CI) 11 to 28). The mean American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score of the surviving patients at latest follow-up was 80.4 (95% CI 72 to 88). In total, 21 patients (23 TARs) underwent subsequent surgery: three implant exchanges, three bearing exchanges and 17 arthrodeses. Neither design of TAR described in this study, the LCS and the Buechel-Pappas, remains currently available. However, based both on this study and on other reports, we believe that TAR using current mobile-bearing designs for patients with end-stage arthritis of the ankle due to inflammatory joint disease remains justified.

Thrombembolic complications after total ankle replacement

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

Revision of failed ankle implants

Total ankle joint replacement (TAR) has been offered as an alternative to ankle joint arthrodesis since the 1970s. TAR offers the benefit of perseveration of joint motion, with potential decreased occurrence of adjacent joint degeneration, and a more expedient path to weight bearing. Since their introduction, TAR devices have undergone a variety of modifications, specifically in regards to the number and type of components used.

End-stage ankle arthritis: arthrodiastasis, supramalleolar osteotomy, or arthrodesis?

End-stage ankle arthritis is a debilitating condition that leads to pain and swelling in the ankle joint, with symptoms aggravated by standing and ambulation. Ankle arthritis commonly results from a history of trauma, or a series of recurrent injuries to the ankle. However, it may develop from other causes such as uneven loading of the ankle joint caused by an alignment deformity or from inflammatory arthritis such as rheumatoid arthritis, gout, or secondary to a serious joint infection. Patients with severe ankle arthritis often have limited ankle motion with an antalgic gait.