STAR™ ankle: long-term results.

BACKGROUND: There has been a resurgence of interest in total ankle replacement (TAR) due to improved results with newer prostheses. However, long-term survivorship data has been limited. The STAR™ Ankle prosthesis is the first three-part prosthesis approved for use in the United States. MATERIALS AND METHODS: Eighty-four total ankle replacements were performed in 80 patients using the STAR™ Ankle prosthesis and followed prospectively. Postoperatively, patients were evaluated with the AOFAS score for pain and function, and serial radiographs were evaluated for stability and alignment of the prosthesis. Implant failure, secondary procedures, and complications were recorded. RESULTS: Ninety-one percent of prostheses remain implanted at an average followup of 9.1 years. The probability of implant survival was 96% at 5 years and 90% at 10 years. An average 39-point improvement in the AOFAS ankle-hindfoot score was noted, from a mean of 43 to a mean of 82 points. We noted a statistically significant increase in both average pain and function sub-scores. Postoperative range of motion averaged 4.5 degrees of dorsiflexion and 35 degrees of plantarflexion. Ninety-two percent of the patients were satisfied with their outcome. Ten patients (13%) developed concerning osteolytic lesions. Change in prosthetic alignment and adjacent joint arthritis were similar to previous reports. We report 21 complications, which included 14 additional surgical procedures. CONCLUSION: The first U.S. prospective long-term survivorship data with the STAR™ Ankle prosthesis found it to be an excellent long-term option for the treatment of ankle arthritis.

Correction of moderate to severe coronal plane deformity with the STAR ankle prosthesis.

BACKGROUND: Prior studies have demonstrated a correlation between the degree of preoperative coronal plane deformity and failure following ankle replacement. We reviewed all of our patients who underwent ankle replacement utilizing the STAR prosthesis from 2000 to 2009 to evaluate the outcome of those with moderate (10 to 19 degrees) and severe (20 degrees or greater) coronal plane deformity. MATERIALS AND METHODS: Out of 130 consecutive patients, 43 patients had at least 10 degrees of preoperative coronal plane deformity. Twenty-five ankles had 10 to 19 degrees degrees of deformity and 18 ankles had 20 degrees or greater deformity. Average age was 66 years. Average length of followup was 41 (range, 12 to 98) months. RESULTS: Average talar preoperative deformity was 17.9 (range, 10 to 29) degrees, while average initial talar postoperative deformity was 3.5 (range, 0 to 12) degrees. Average final talar postoperative deformity was 4.7 (range, 0 to 14) degrees. Preoperative and final correction of deformity was statistically significant (p < 0.01), but there was no significant difference between initial and final postoperative correction. Overall, recurrence of the preoperative coronal plane deformity occurred in six of 43 patients (14%). All three patients who had deformities over 25 degrees developed recurrences. Correction of the coronal plane deformities was achieved by using intraoperative soft-tissue balancing, including deltoid ligament release in 12 patients and lateral ligament reconstruction in one patient. Deltoid ligament release was found to be necessary for all patients with greater than 18 degrees of varus plane deformity. CONCLUSION: Correction of moderate to severe coronal plane deformity with the STAR prosthesis was achievable with only soft-tissue balancing procedures with predictable results especially for deformities less than 25 degrees.

Prospective controlled trial of STAR total ankle replacement versus ankle fusion: initial results.

BACKGROUND: Mobile-bearing ankle replacements have become popular outside of the United States over the past two decades. The goal of the present study was to perform a prospective evaluation of the safety and efficacy of a mobile-bearing prosthesis to treat end stage ankle arthritis. We report the results of three separate cohorts of patients: a group of Scandanavian Total Ankle Replacement (STAR) patients and a control group of ankle fusion patients (the Pivotal Study Groups) and another group of STAR total ankle patients (Continued Access Group) whose surgery was performed following the completion of enrollment in the Pivotal Study. MATERIALS AND METHODS: The Pivotal Study design was a non-inferiority study using ankle fusion as the control. A non-randomized multi-centered design with concurrent fusion controls was used. We report the initial perioperative findings up to 24 months following surgery. For an individual patient to be considered an overall success, all of the following criteria needed to be met: a) a 40-point improvement in total Buechel-Pappas ankle score, b) no device failures, revisions, or removals, c) radiographic success, and d) no major complications. In the Pivotal Study (9/00 to 12/01), 158 ankle replacement and 66 arthrodesis procedures were performed; in the Continued Access Study (4/02 to 10/06), 448 ankle replacements were performed, of which 416 were at minimum 24 months post-surgery at time of the database closure. RESULTS: Major complications and need for secondary surgical intervention were more common in the Pivotal Study arthroplasty group than the Pivotal Study ankle fusion group. In the Continued Access Group, secondary procedures performed on these arthroplasty patients decreased by half when compared with the Pivotal Arthroplasty Group. When the Pivotal Groups were compared, treatment efficacy was higher for the ankle replacement group due to improvement in functional scores. Pain relief was equivalent between fusion and replacement patients. The hypothesis of non-inferiority of ankle replacement was met for overall patient success. CONCLUSION: By 24 months, ankles treated with STAR ankle replacement (in both the Pivotal and Continued Access Groups) had better function and equivalent pain relief as ankles treated with fusion.

Osteoarthritis of the ankle: the role of arthroplasty.

Total ankle arthroplasty was developed to reduce pain and retain motion of the ankle joint in patients with osteoarthritis. The ankle joint has unique, complex anatomic and biomechanical characteristics that must be considered in a successful total ankle arthroplasty prosthesis. Initial designs from the 1960s to the 1970s had many failures. Current designs use two or three components, and recent reports on total ankle arthroplasty show consistent good to excellent intermediate clinical results, with up to 90% decreased pain and high patient satisfaction. The follow-up time of these studies is limited, however, and long-term studies with 10- to 15-year follow-ups are needed. Also, a wide variety of complications has been reported, including osteomyelitis and osteolysis. To limit the number of complications and improve clinical outcome of total ankle arthroplasty, careful patient selection and surgeon experience are important.

Scandinavian Total Ankle Replacement: 15-Year Follow-up.

BACKGROUND: Over the past decade, total ankle arthroplasty (TAA) has become a mainstay in the treatment of end-stage ankle arthritis. Currently in its fourth generation, the Scandanavian Total Ankle Replacement (STAR) is the only 3-piece mobile bearing ankle prosthesis available in the United States. Our current study reports implant survivorship at 15 years and patient outcomes for a subset of these survivors available for study. METHODS: Eighty-four TAAs were performed between 1998 and 2000. Metal component survivorship at 15 years was calculated with a Kaplan-Meier curve. Twenty-four (29%) of 84 patients were available for participation with a minimum 15-year follow-up. Any radiographic changes were documented. All additional procedures and complications were recorded. Clinical findings, self-reported performance and pain evaluations, and AOFAS ankle/hindfoot scores were noted. RESULTS: Metal implant survival was 73% at 15 years. Of the 24 patients available for clinical evaluation, 18 of 24 patients (70.7%) had no change in prosthetic alignment from the immediate postoperative radiograph. Only 1 subtalar fusion was required for symptomatic adjacent joint arthritis. Three patients sustained a broken polyethylene component. AOFAS scores improved from an average of 39.6 points preoperatively, to an average of 71.6. More than half (52.4%) of patients with retained implants required an additional surgical procedure; 3 required 2 additional procedures. The average time to subsequent procedure was 10.2 years. CONCLUSION: Our small cohort demonstrated STAR ankles with retention at 9 years were highly likely to survive to 15 years, and patients continued to have significant improvement in pain relief and minimal decrease in function. At 15 years from TAA, metal survivorship was 73%. As with all ankle replacements, supplementary procedures were common. LEVEL OF EVIDENCE: Level IV, case series.

Stress fracture as a complication of autogenous bone graft harvest from the distal tibia.

BACKGROUND: Autogenous bone graft from the distal tibia provides cancellous bone graft for foot and ankle operations, and it has osteogenic and osteoconductive properties. The site is in close proximity to the foot and ankle, and published retrospective studies show low morbidity from the procedure. METHODS: One-hundred autografts were obtained from the distal tibia between 2000 and 2003. In four cases the distal tibial bone graft harvest resulted in a stress fracture. There were three women and one man. RESULTS: The average time of diagnosis of the stress fracture from the operation was 1.8 months. All stress fractures healed with a short course (average 2.4 months) of cast immobilization. CONCLUSIONS: This study demonstrated that a stress fracture from the donor site of autogenous bone graft of the distal tibia occurs and can be successfully treated nonoperatively.

Keratotic disorders of the plantar skin.

Keratotic lesions on the plantar aspect of the foot develop beneath an osseous prominence and can result in substantial disability. This occurs because, during normal gait, the metatarsal head area is subjected to more prolonged stress than any other area on the plantar aspect of the foot. In the treatment of this disorder, it is imperative to establish the etiology, among many possibilities, and then address the specific pathology accordingly.

The bunionette deformity.

The bunionette deformity results in pain about the lateral and/or the plantar aspect of the fifth metatarsal head. It is important to carefully assess the deformity anatomically in order to select the proper surgical procedure to correct this painful affliction. Knowledge of pathoanatomy and certain surgical procedures can be used to correct the deformity.

Perioperative complication rate of total ankle replacement is reduced by surgeon experience.

BACKGROUND: Recent studies suggest the perioperative complication rate of total ankle arthroplasty decreases as a surgeon becomes familiar with the procedure. This study tests the hypothesis that the number of perioperative adverse events will decrease as surgeon experience with total ankle replacement increases. METHODS: Ten surgeons completed retrospective chart and radiographic reviews of their first 10 cases as well as 10 subsequent cases of the Scandinavian Total Ankle Replacement (STAR). Not all surgeons completed 10 cases within the allotted time periods, and two patients were excluded for less than 3-month follow-up, resulting in 187 cases for review. The surgeons performed an average of 12.8 (range, 0-61) STARs between these two time periods. Cases were divided into Early Group if they were among the first five STARs a surgeon performed and Late Group if they were after the first five. RESULTS: The average patient age was 60.4 +/- 12.8 years. The etiology of arthrosis included 96 (51%) of 187 posttraumatic, 49 (26%) idiopathic, and 33 (18%) rheumatoid. Patients in Early Group had a 3.1 times greater chance of having a perioperative adverse event (95% CI 1.6-6.1, p <.001), and a 3.2 times greater chance of having a perioperative wound problem (95% CI 1.5-6.8, p =.002) than patients in Late Group. Patients in Early Group took 1 week longer to heal their wounds than patients in Late Group (4.5 vs. 3.5 weeks, p =.046). CONCLUSIONS: This study shows a decrease in the perioperative adverse event rate commensurate with surgeon experience with STAR. In contrast to other reports, this study was unable to show a decrease in the number of perioperative fractures with increasing surgeon experience. This information is important for planning how best to train surgeons new to total ankle replacement and for patient counseling regarding the potential risks of the procedure.

A review of rheumatoid arthritis affecting the foot and ankle.

Rheumatoid arthritis is a systemic disease that often affects the foot and ankle. Approximately 20% of patients with rheumatoid arthritis present initially with foot and ankle symptoms, and most patients will eventually develop foot and ankle symptoms. Although early intervention includes conservative measures, operative treatment often is needed to adequately treat rheumatoid patients. Treatment of foot and ankle problems in patients with rheumatoid arthritis is directed to maintaining ambulatory capacity. This article reviews the clinical presentation, evaluation, and treatment of rheumatoid arthritis affecting the foot and ankle.

Functional evaluation of the Scandinavian Total Ankle Replacement.

The purpose of this study was to evaluate the function of the ankle joint during walking before and after Scandinavian Total Ankle Replacement (STAR). Nine patients (six males and three females) with an average age of 65 years, scheduled for unilateral total ankle replacement for osteoarthritis and rheumatoid arthritis, were evaluated both preoperatively and postoperatively in a gait analysis laboratory. Arthroplasty patients showed reduced range of motion at the ankle compared to normal controls. Postoperative arthroplasty subjects had significantly improved external ankle dorsiflexion moment, the moment that affects the plantarflexor muscles, when compared to their preoperative status. The moment in arthroplasty patients was increased, indicating improved function of the ankle joint.

The history of the STAR total ankle arthroplasty.

The STAR ankle replacement prosthesis has almost a 30-year history. The current FDA study of the device in the United States is very encouraging. The prosthesis does show great promise but needs further study. Further elucidation of the postoperative radiographs and the various areas of lucency and their significance should be studied. The learning curve for implantation is very steep.

Ankle arthroplasty with preoperative coronal plane deformity: short-term results.

The treatment of coronal plane deformity during total ankle arthroplasty is understood poorly. This study tests the hypotheses that preoperative coronal plane malalignment and incongruence of the ankle can be corrected and maintained for 2 years with total ankle replacement, and that factors can be identified that place ankles at risk of having progressive edge-loading develop. Of 86 consecutive patients who had total ankle replacement, 35 had preoperative coronal plane alignment > or =10 degrees. Lateral ligament reconstruction was done in seven patients and superficial deltoid release was done in four patients at the time of ankle replacement. Ankles with talar and tibial deformities improved talar and tibial alignment toward a neutral weightbearing axis postoperatively. Ankles with only a talar deformity improved the talar alignment toward a neutral weightbearing axis postoperatively. No changes in alignment were shown during the subsequent 2 years. Postoperative ankle articulations were congruent. Patients with preoperative incongruent joints are 10 times more likely to have progressive edge-loading develop than patients with congruent joints. Surgeons must be attentive to coronal plane alignment during and after ankle replacement. Longer followup is needed to assess the longevity of the correction and the impact of minor malalignment on implant wear.