The AES total ankle replacement: A mid-term analysis of 93 cases

Total Ankle Replacement Infections: A Systematic Review of the Literature

Periprosthetic infection (PJI) after TAR is a serious complication, often requiring further surgery, including revision arthroplasty, conversion to ankle arthrodesis, or even amputation. This systematic review aims to summarize the current evidence on the management of TAR PJI and provide a comprehensive overview of this topic, especially from an epidemiologic point of view. Three different databases (PubMed, Scopus, and Web of Science) were searched for relevant articles, and further references were obtained by cross-referencing. Seventy-one studies met the inclusion criteria, reporting on cases of TAR PJI. A total of 298 PJIs were retrieved. The mean incidence of PJI was 3.8% (range 0.2-26.1%). Furthermore, 53 (17.8%) were acute PJIs, whereas most of them (156, 52.3%) were late PJIs. Most of the studies were heterogeneous regarding the treatment protocols used, with a two-stage approach performed in most of the cases (107, 35.9%). While the prevalence of ankle PJI remains low, it is potentially one of the most devastating complications of TAR. This review highlights the lack of strong literature regarding TAR infections, thus highlighting a need for multicentric studies with homogeneous data regarding the treatment of ankle PJI to better understand outcomes.

Outpatient Total Ankle Arthroplasty (TAA) as a Rising Alternative to Inpatient TAA: A Database Analysis

BACKGROUND

There is growing evidence that total ankle arthroplasty (TAA) can safely be performed as an outpatient procedure, with the benefit of decreased health care expenses and improved patient satisfaction. The purpose of our study was to compare readmissions, arthroplasty failures, infections, and annual trends between outpatient and inpatient TAA using a large publicly available for-fee database.

METHODS

The PearlDiver Database was queried to identify outpatient and inpatient TAA-associated claims for several payer types from January 2010 to October 2021. Preoperative patient characteristics and annual trends were compared for inpatient and outpatient TAA. International Classification of Diseases, Ninth and Tenth Revision, diagnosis codes were used to identify infections and arthroplasty failures. Complications rates were compared after matching patients by age, gender, and the following comorbidities: diabetes, smoking, congestive heart failure (CHF), hypertension (HTN), obesity, and chronic kidney disease (CKD).

RESULTS

A total of 12 274 patients were included in the final exact-matched analysis for complications, with 6137 patients in each group. Outpatients had a significantly lower rate of readmission within 90 days (2.6% vs 4.0%, P < .001), arthroplasty failure (4.1% vs 6.9%, P < .001), and infection (2.4% vs 3.1%, P = .015). Among database enrollees, outpatient TAA has risen in proportion to inpatient TAA from 2019 to 2021.

CONCLUSION

Outpatient TAA had lower rates of risk-adjusted readmission, arthroplasty failure, and infection compared to inpatient TAA.

LEVEL OF EVIDENCE

Level III, retrospective comparative database study.

A Propensity Score Matched Exploration of Infection in Primary Total Ankle Arthroplasty

BACKGROUND

Infection is a serious complication of primary total ankle arthroplasty (TAA) and can lead to implant failure and revision surgery. Various demographic, comorbidity, and surgical factors have been associated with an increased risk of infection. However, the evidence base remains limited, and further research is needed regarding infection in TAA. This study aims to analyze risk factors of infection and explore outcomes following infected TAA.

METHODS

A retrospective cohort study was conducted using data from a single institution from 2002 to 2022. Patients who underwent primary TAA and had subsequent infection were identified through annual registry surveillance and matched using propensity score matching (PSM) based on various demographic, comorbidity, and surgical factors. Demographics were compared between the matched groups using Mann-Whitney U test and Fisher exact test. The outcomes following infection were identified and summarized using descriptive statistics.

RESULTS

A total of 1863 patients who underwent primary TAA were identified, and 19 were diagnosed with an infection. The identifiable overall infection rate was 1.0%. After PSM, there were no significant differences in the difference in age, gender, BMI, and smoking status between the infected and control cohort. There was a statistically significant increase in the rate of diabetes in the infected cohort. The subsequent surgical intervention resulted in limb salvage in 18 (94.7%) cases. Out of the total number of cases, 2-stage revision to total ankle replacement was performed in 7 cases, whereas revision to arthrodesis and isolated polyethylene exchange were each carried out in 4 cases. One patient had to undergo amputation; however, at the time of the most recent follow-up, all patients were found to be free of infection.

CONCLUSION

This study demonstrated high rates of a history of smoking and diabetes in the infected TAA cohort. The diabetes rate in the infected group was significantly higher than the noninfected controls. Two-stage revision to total ankle replacement was performed in 7 cases, and revision to arthrodesis and isolated polyethylene exchange were each carried out in 4 cases. Overall, a high rate of limb salvage was reported.

LEVEL OF EVIDENCE

Level III, case-control study.

Postoperative Infection Rates After Total Ankle Arthroplasty: A Comparison With and Without the Use of a Surgical Helmet System

Following total joint arthroplasty, surgical site infections (SSI) and periprosthetic joint infections (PJI) are associated with increased patient morbidity and healthcare utilization. Current positive-pressure surgical sterile helmet system (SHS) were developed as a feasible, useful version of the body exhaust system.The use of SHS has not yet been proven to decrease infection rates in the orthopedic literature. The primary purpose of this study is to compare the infection rates between patients who underwent total ankle arthroplasty (TAA) with a surgical team wearing SHS versus without SHS.A retrospective chart review in patients undergoing primary TAA with the surgeon wearing SHS (Group 1) or standard surgical attire (Group 2) was conducted. The primary outcome was postoperative SSI and PJI. The rate of wound complications, revision rates, and associated procedures were also analyzed. We identified 109 patients in Group 1 and 151 patients in Group 2. The rate of SSI was 12.8% in Group 1 and 14.6% in Group 2 (p = .411). The rate of PJI was 0.92% in Group 1 and 2.6% in Group 2 (p = .411). There was no difference in revision rates between the two groups. This study suggests that SHS does not appear to protect against postoperative SSI or PJI after TAA. Conversely, we did not find a higher infection rate compared to standard surgical attire despite recent in-vitro studies suggesting SHS as a source of wound contamination. The utility of SHS does not appear to influence the prevalence of postoperative SSI or PJI.

Revision Rates After Total Ankle Replacement: A Comparison of Clinical Studies and Arthroplasty Registers

BACKGROUND

The aim of this study was to assess the outcome of total ankle replacement (TAR) regarding revision rates by comparing clinical studies of the last decade to data displayed in arthroplasty registers. The secondary aim was to evaluate whether dependent clinical studies show a superior outcome to independent publications. Additionally, revision rates of mobile bearing implants (MB-TARs) were compared to those of fixed bearing implants (FB-TARs).

METHODS

Clinical studies on TARs between 2010 and 2020 were systematically reviewed, with the endpoint being a revision for any reason. The parameter "revision rate per 100 observed component years (CYs)" was calculated for each publication. The pooled revision rate for clinical studies was compared to the data reported in arthroplasty registers. In a second step, revision rates were subdivided and analyzed for independent and dependent publications and for FB-TARs and MB-TARs.

RESULTS

A total of 43 publications met the inclusion criteria comprising 5806 TARs. A revision rate of 1.8 per 100 observed CYs was calculated, corresponding to a 7-year revision rate of 12.6%. The 3 arthroplasty registers included showed revision rates ranging from 8.2% to 12.3% after 7 years. No significant difference between dependent and independent publications nor between FB-TARs and MB-TARs was detected.

CONCLUSION

Revision rates of clinical studies and arthroplasty registers are comparable. Surgeons can compare their own revision rates with those from this study. Dependent studies do not seem to be biased, and no superiority for one bearing type can be described.

LEVEL OF EVIDENCE

Level III, systematic review of level III studies.

Clinical-radiological outcomes and complications after total ankle replacement through a lateral transfibular approach: a retrospective evaluation at a mid-term follow-up

PURPOSE

Degenerative ankle arthropathy is a debilitating and increasingly widespread condition with worsening of quality of life. In last years, total ankle replacement has increased indications, thanks to advances in surgical technique, materials and design that provided new solutions for surgeons. The purpose of this study is to evaluate the effectiveness of total ankle replacement (TAR), implanted using a trans-fibular lateral approach in patients with high-grade degenerative arthropathy, in terms of clinical, functional and radiological outcomes and possible complications.

METHODS

This retrospective study included 73 patients, aged between 47 and 79 years (mean age 61.7 ± 14.2 years), who underwent trans-fibular total ankle arthroplasty. All patients were followed up for at least two years post-operatively with mean follow-up 31.2 ± 8.1 months and have been evaluated clinically and radiographically both pre-operatively and post-operatively.

RESULTS

Patients demonstrated a significant improvement in average AOFAS score, SF-36 score and VAS scale. Average plantarflexion improved from 9.9° ± 4.2 to 18.4° ± 6.3 and dorsiflexion from pre-operative mean value of 6.8° ± 5.8 to 17.2° ± 3.1 post-operative. Complications recorded in our series were 16 (21.9%), specifically 2 major complications and 14 minor complications.

CONCLUSIONS

This study found that trans-fibular total ankle replacement is a safe and effective option for patients with ankle osteoarthritis, resulting in improvement of patient-reported outcomes, range of motion, and radiographic parameters. However, further studies are required to determine long-term performance of these implants.

Positive and negative factors for the treatment outcomes following total ankle arthroplasty? A systematic review

BACKGROUND

Patient selection, surgeon's experience and implant design play an integral role and affect the treatment outcomes of total ankle arthroplasty (TAA). The aims of this study were to investigate the positive and negative attributes that correlate with different clinical and radiographic outcomes.

METHODS

Eight-nine studies matched the inclusion criteria: (1) studies of primary TAA with uncemented prosthesis; (2) mean follow-up of no less than 2-year; (3) reports of clinical and radiographic outcomes, and exclusion criteria: (1) non-English study; (2) more than one type of prosthesis without separated data; (3) kin studies with shorter follow-up or smaller cohort. Age, etiology, preoperative deformity, surgeon's experience, follow-up duration and prosthetic type were studied with respect to different outcomes by mixed-effects logistic regression analysis.

RESULTS

Patients factor: older patients reported less pain or stiffness and demonstrated less radiographic loosening which did not require additional surgical intervention. More traumatic arthritis experienced adjacent joints degeneration after TAA. Surgeon factor: less experienced surgeons had more intraoperative complications. Lack of experience for complications management without implant retrieval during early period might result in more revisions or fusion was done. Prosthetic factor: updated instrumentation decreased malalignment. If the polyethylene (PE) insert was significantly narrower than the metal components more implant instability and subsequent severe particulate wear was seen. Designs with flat-on-flat articulation and ridge at the center of the talar component associated with more PE fracture. Minimal bone resection reduced postoperative fractures. A flat cut of the tibial component and a flat undersurface with press-fit by two screws or pegs of the talar component demonstrated less postoperative fractures, whereas a syndesmosis fusion and a small triangular shape with one central fin of the talar component experienced more loosening which did not require additional surgery. Anatomic conical shape of the talar component seemed to reduce adjacent joint degeneration. Finally, fewer failures were found in patients who received HINTEGRA and Salto Talaris.

CONCLUSIONS

Based on our investigation, some positive and negative factors for different clinical and radiographic outcomes were found, which should be taken into consideration in clinical practice and ankle implant design.

Association of Peripheral Vascular Disease With Complications After Total Ankle Arthroplasty

BACKGROUND

Despite limited evidence, peripheral vascular disease is often cited as a contraindication for total ankle arthroplasty. The purpose of our study was to identify whether peripheral vascular disease in patients undergoing total ankle arthroplasty increased the rate of infection, postoperative irrigation and debridement, or failure of the implant.

METHODS

The PearlDiver Database was used to identify Medicare patients who underwent a total ankle arthroplasty from 2005 to 2014. These data were then analyzed for postoperative infections within 90 days, subsequent irrigation and debridements, and failure of total ankle arthroplasties. A diagnosis of preoperative peripheral vascular disease only included those patients who had peripheral vascular disease as an ICD-9 diagnosis code and underwent a preoperative lower extremity angiogram prior to total ankle arthroplasty. Medical comorbidities were identified using ICD-9 diagnosis codes. Three multivariable logistic regression models were then developed in order to identify risk factors associated with postoperative infections and failure after total ankle arthroplasty.

RESULTS

A total of 10 698 Medicare patients who underwent a primary total ankle arthroplasty were identified. There were 334 patients who had a postoperative infection within 90 days of their total ankle arthroplasty, and 95 of those patients required an irrigation and debridement. Regression analysis demonstrated that patients with peripheral vascular disease had the greatest risk of developing a postoperative infection within 90 days (OR 2.85, P < .01), requiring an irrigation and debridement postoperatively (OR 4.87, P < .001), and having a total ankle arthroplasty failure at any time point postoperatively (OR 2.51, P < .001).

CONCLUSIONS

Our study suggests that preoperative peripheral vascular disease is a significant risk factor for an acute postoperative infection, postoperative irrigation and debridement, and failure of the implant in Medicare patients undergoing a total ankle arthroplasty.

LEVEL OF EVIDENCE

Level III, therapeutic.

Infections in primary total ankle replacement: Anterior approach versus lateral transfibular approach

BACKGROUND

Total ankle replacement (TAR) represents an alternative to fusion for the treatment of end-stage ankle osteoarthritis. The aim of the present study was to retrospectively assess the frequency of infections between TARs with anterior and lateral transfibular approach at 12-months follow-up.

METHODS

81 TARs through an anterior approach and 69 TARs through a lateral approach were performed between May 2011 and July 2015. We compared surgical time and tourniquet time, as well as superficial and deep infections frequency during the first 12 postoperative months.

RESULTS

In the anterior approach group, there were 3 (3.7%) deep infections and 4 (4.9%) superficial wound infections. In the lateral approach group, there were 1 (1.4%) deep infection and 2 superficial wound infections (2.9%). There were not statistically significant differences between the groups. There was a significant difference between anterior approach (115minutes) and lateral approach group (179minutes) in terms of surgical time (P<0.001).

CONCLUSIONS

The frequency of superficial and deep periprosthetic infections during the first postoperative year was not significantly different in the lateral approach group compared to the anterior approach group, despite the significantly longer surgical time in the lateral transfibular approach group.

Medium to long-term results of 130 Ankle Evolutive System total ankle replacements-Inferior survival due to peri-implant osteolysis

BACKGROUND

The study reports the medium to long-term results of 130 Ankle Evolutive System total ankle replacements operated at a single-centre. Previously high amount of peri-implant osteolysis was reported from the same material.

METHODS

Between 2002 and 2008 one hundred and thirty consecutive ankles replaced with AES ankle prosthesis were followed both radiologically and clinically.

RESULTS

The five-year survival was 87.3% (95% confidence interval (CI) 80.0-92.0%), and ten-year survival 74.9% (95% confidence interval (CI) 65.4-82.2%) at a median follow-up time of 96 months (range 2-161; 8 years). Peri-implant osteolysis was found in 91 (70%) ankles, marked in 78 (60%). 44 ankles (34%) have been revised by filling of the cavities, 24 (18%) by fusion, and 6 by further replacement, resulting in the revision rate of 58%. Osteolysis was the main reason for all revisions. The improvement of the Kofoed Score and pain points was significant (all p<0.0001), and the subjective patient satisfaction was good.

CONCLUSIONS

Outcome of the current study was seriously affected by osteolysis and is inferior compared to previous reports.

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.

Post-Traumatic Periprosthetic Tibial and Fibular Fracture After Total Ankle Arthroplasty: A Case Report

Periprosthetic fractures after total ankle arthroplasty are uncommon, with most cases occurring intraoperatively. We describe a post-traumatic periprosthetic fracture of the distal tibia and fibula after total ankle arthroplasty that was treated with minimally invasive plate osteosynthesis. It is important for orthopedic surgeons not only to recognize the risk factors for postoperative periprosthetic total ankle arthroplasty fractures, but also to be familiar with the treatment options available to maximize function and minimize complications. The design of the tibial prosthesis and surgical techniques required to prepare the ankle joint for implantation are important areas of future research to limit the risk of periprosthetic fractures.

Total ankle replacement

BACKGROUND

About 1% of adults suffer from painful osteoarthritis of the ankle. The current literature contains no information on the percentage of such patients who derive long-term relief of symptoms from conservative treatment. Advanced ankle osteoarthritis can be treated with non-joint-preserving measures, such as total ankle replacement and ankle fusion.

METHODS

This review is based on selected relevant publications, guidelines from Germany and abroad, and the authors' personal experience.

RESULTS

Before surgery is considered, conservative measures such as physiotherapy and orthopedic aids should be used to the fullest possible extent. No randomized trials have yet been published comparing total ankle replacement with ankle fusion. Total ankle replacement with newer types of prosthesis yields good to very good intermediate-term and long-term results, with mean success rates of up to 90% at 10 years (range, 68-100%). Independent risk factors for the failure of ankle replacement are age over 70 years (odds ratio [OR] 3.84), primary osteoarthritis (OR 7.19), post-traumatic osteoarthritis (OR 6.2), and type of prosthesis (e.g., single hydroxyapatite coating: OR 15.04). The average range of motion of the replaced ankle joint is 25° to 30°, with values as high as 60°.

CONCLUSION

Total ankle replacement is a good treatment option for complete, end-stage ankle arthritis. It can restore joint function and make the patient mobile with little or no pain. There are, however, many contraindications to be taken into account. There is a need for further studies of the biomechanics of arthritic and replaced ankle joints and for long-term follow-up studies of total ankle replacement.

Periprosthetic osteolysis after AES total ankle replacement: Conventional radiography versus CT-scan

BACKGROUND

The aim of this study was to compare conventional X-rays and CT-scan in detecting peri-prosthetic osteolytic lesions, a major concern after total ankle replacement (TAR).

METHODS

We prospectively assessed 50 patients (mean age 56 years), consecutively operated on by the same senior surgeon, between 2003 and 2006 and with a mean follow-up period of 4 years (range, 2-6.2). The component used was AES total ankle replacement. The etiologies for total ankle arthroplasty were: posttraumatic in 50%, osteoarthritis secondary to instability in 36%. Plain radiographs were analyzed by 4 independent observers, using a 10-zone protocol (location) and 5 size categories.

RESULTS

At 4-year follow-up, all patients had been CT-scan assessed with the same protocol by 2 independent observers. Plain radiographs showed dramatic progression of severe periprosthetic lyses (>10mm): from 14% to 36% of interface cysts for the tibial component respectively at 2 and 4-year follow-up and from 4% to 30% for the talar implant. The talar component was more accurately assessed by CT-scan (mean frontal and sagittal talar lesion: from 270 mm2 to 288 mm2 for CT-scan versus 133 mm2 to 174 mm2 for X-rays). For tibial cysts, axial views showed larger lesions (313 mm2 than frontal (194 mm2) or sagittal (213.5 mm2) views. At 4-year follow-up, 24% of patients had revision with curetage or arthrodesis, and at 7 years follow-up 38% were revised.

CONCLUSION

These results are similar to recent AES series, justifying withdrawal of this device. CT-scan was more accurate than X-rays for detecting and quantifying periprosthetic osteolysis. We recommend a yearly radiological control and CT-scan in case of lesion on X-rays.

Infected total ankle arthroplasty: risk factors and treatment options

BACKGROUND

Infections in total ankle arthroplasty are a serious complication, about which there is little information in the current literature.

METHODS

This is a retrospective review of infected total ankle arthroplasty at one institution from 1995 to 2012. Risk factors were compared between patients with infected total ankle arthroplasty and age- and sex-matched patients who did not have infection (control patients) within the same time period.

RESULTS

966 patients with total ankle arthroplasty were reviewed, and 29 cases of infected total ankle arthroplasty (3.2%) were identified. The incidence of infection in primary ankle arthroplasty was 2.4% and in revision arthroplasty was 4%. Risk factors for infection in our cohort included diabetes, prior ankle surgery, and wound healing problems more than 14 days postoperatively. No significant difference was found between groups with respect to risk factors including smoking, body mass index, and operative time. At latest follow-up, none of the patients had signs of persistent infection. Operative intervention of infected total ankle arthroplasty resulted in limb salvage in 79% of cases (a 21% amputation rate). At final follow-up, 65.5% of cases were infection-free with retained arthroplasty. This was achieved by irrigation and debridement alone, 1-stage fusion, and most often 2-stage revision. The final outcome was fusion in 3 of 29 cases (10.3%).

CONCLUSIONS

Given the morbidity of infected ankle arthroplasty, careful consideration should be made about performing arthroplasty in patients with multiple prior surgeries and comorbidities that predispose to wound-healing difficulties.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Review of 103 Swedish Healthcare Quality Registries

BACKGROUND AND OBJECTIVES

In the past two decades, an increasing number of nationwide, Swedish Healthcare Quality Registries (QRs) focusing on specific disorders have been initiated, mostly by physicians. Here, we describe the purpose, organization, variables, coverage and completeness of 103 Swedish QRs.

METHODS

From March to September 2013, we examined the 2012 applications of 103 QRs to the Swedish Association of Local Authorities and Regions (SALAR) and also studied the annual reports from the same QRs. After initial data abstraction, the coordinator of each QR was contacted at least twice between June and October 2013 and asked to confirm the accuracy of the data retrieved from the applications and reports.

RESULTS

About 60% of the QRs covered ≥80% of their target population (completeness). Data recorded in Swedish QRs include aspects of disease management (diagnosis, clinical characteristics, treatment and lead times). In addition, some QRs retrieve data on self-reported quality of life (EQ5D, SF-36 and disease-specific measures), lifestyle (smoking) and general health status (World Health Organization performance status, body mass index and blood pressure).

CONCLUSION

Detailed clinical data available in Swedish QRs complement information from government-administered registries and provide an important source not only for assessment and development of quality of care but also for research.

The treatment and outcome of peri-prosthetic infection of the ankle: a single cohort-centre experience of 34 cases

The treatment of peri-prosthetic joint infection (PJI) of the ankle is not standardised. It is not clear whether an algorithm developed for hip and knee PJI can be used in the management of PJI of the ankle. We evaluated the outcome, at two or more years post-operatively, in 34 patients with PJI of the ankle, identified from a cohort of 511 patients who had undergone total ankle replacement. Their median age was 62.1 years (53.3 to 68.2), and 20 patients were women. Infection was exogenous in 28 (82.4%) and haematogenous in six (17.6%); 19 (55.9%) were acute infections and 15 (44.1%) chronic. Staphylococci were the cause of 24 infections (70.6%). Surgery with retention of one or both components was undertaken in 21 patients (61.8%), both components were replaced in ten (29.4%), and arthrodesis was undertaken in three (8.8%). An infection-free outcome with satisfactory function of the ankle was obtained in 23 patients (67.6%). The best rate of cure followed the exchange of both components (9/10, 90%). In the 21 patients in whom one or both components were retained, four had a relapse of the same infecting organism and three had an infection with another organism. Hence the rate of cure was 66.7% (14 of 21). In these 21 patients, we compared the treatment given to an algorithm developed for the treatment of PJI of the knee and hip. In 17 (80.9%) patients, treatment was not according to the algorithm. Most (11 of 17) had only one criterion against retention of one or both components. In all, ten of 11 patients with severe soft-tissue compromise as a single criterion had a relapse-free survival. We propose that the treatment concept for PJI of the ankle requires adaptation of the grading of quality of the soft tissues.

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.

Clinical and radiographic outcomes of the mobility total ankle arthroplasty system: early results from a prospective multicenter study

BACKGROUND

The Mobility Total Ankle System is a third-generation design consisting of a 3-component, cementless, unconstrained, mobile-bearing prosthesis. This study reports the early results of a prospective multicenter study of the Mobility prosthesis.

METHODS

Eighty-eight Mobility total ankle arthroplasties (TAAs) were implanted in 85 patients. The most common underlying diagnosis was posttraumatic arthritis (53%). Ankles were classified according to the Canadian Orthopedic Foot and Ankle Society (COFAS) end-stage ankle arthritis classification system. Coronal plane deformity was quantified preoperatively. Patients were reviewed at regular intervals postoperatively, with clinical and radiographic assessment. The mean follow-up time was 40 months (range, 30-60 months).

RESULTS

Type 1 ankle arthritis was demonstrated in 44 ankles (50%). No patient had preoperative coronal plane angulation greater than 20 degrees. In 32 ankles (36%) the preoperative coronal alignment was neutral, and in 34 ankles (39%) the deformity was less than 10 degrees. The mean American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot score improved from 38.2 (range, 12-59) preoperatively to 74.8 (range, 46-100) postoperatively. Bone-implant interface abnormalities were identified in 33 ankles with a retained prostheses (43%). Thirty (91%) of these involved zones around the tibial plate. In total, 8 TAAs required revision, 6 for aseptic loosening, 1 for talar migration, and 1 for deep infection. There was 1 conversion to arthrodesis for component malpositioning and 1 transtibial amputation for chronic regional pain syndrome. Six patients were being investigated for ongoing pain. The cumulative survival was 89.6% (95% confidence interval, 80.8-94.8) at 3 years and 88.4% (95% confidence interval, 79.3-93.9) at 4 years.

CONCLUSION

Early results of the Mobility TAA for independent researchers do not match those reported by other surgeons. Good pain relief and improved function were achieved postoperatively in 72 ankles (82%). High rates of bone-implant interface abnormalities around the tibial plate are concerning but require longer follow-up to determine their clinical significance.

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.

Mobile- and fixed-bearing total ankle prostheses: is there really a difference?

Approximately 1% of the world's adult population is affected by ankle osteoarthritis (OA). Therapeutic options include conservative and surgical measures. Because of substantial progress in total ankle replacement, ankle fusion is no longer the "gold standard" therapy for end-stage ankle OA. Various ankle prostheses have been designed and are currently available. This article reviews the in vitro studies addressing the biomechanics and kinematics of the replaced ankle. Furthermore, a systematic literature review was conducted to assess possible differences in clinical outcomes, including prosthesis survivorship and postoperative range of motion between mobile- and fixed-bearing total ankle prostheses.

Risk factors for periprosthetic ankle joint infection: a case-control study

BACKGROUND

Periprosthetic ankle joint infection is a feared complication of total ankle arthroplasty because the implant fails in the majority of cases. However, risk factors for developing these infections are unknown.

METHODS

We aimed to determine risk factors for infection in a matched case-control study that included twenty-six patients with periprosthetic ankle joint infection and two control groups, each consisting of fifty-two patients.

RESULTS

The prevalence of periprosthetic ankle joint infection within our cohort was 4.7%. Four infections (15%) had a hematogenous origin and twenty-two (85%), an exogenous origin. Staphylococcus aureus was the most common pathogen, followed by coagulase-negative staphylococci. Preoperative predisposing factors associated with infection included prior surgery at the site of infection (odds ratio [OR] = 4.56, 95% confidence interval [CI] = 0.98 to 21.35, and OR = 4.78, 95% CI = 1.53 to 14.91, in comparison with the two control groups) and a low American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score (35.8 versus 49.8 and 47.6 in the two control groups, p ≤ 0.02). The mean duration of the index surgery was significantly longer in the case group than in both control groups (119 versus eighty-four and ninety-three minutes, p ≤ 0.02). After surgery, persistent wound dehiscence (OR = 15.38, 95% CI = 2.91 to 81.34, p = 0.01, in comparison with both control groups) and secondary wound drainage (OR = 7.00, 95% CI = 1.45 to 33.70, and OR = 5.31, 95% CI = 1.01 to 26.78, in comparison with the two control groups, p ≤ 0.04) were associated with the development of a periprosthetic ankle joint infection.

CONCLUSIONS

Patients at risk for periprosthetic ankle joint infection following total ankle arthroplasty include those with a history of surgery on the ankle, a low preoperative AOFAS hindfoot score, and a long operative time. Postoperatively, patients with a prolonged wound dehiscence or a secondary wound-healing problem are also at risk for infection.

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.

Total ankle replacements: an overview

One of the most widely debated topics amongst foot and ankle surgeons is the treatment of end stage arthritis. With the advent of the newer generation of total ankle replacement (TAR), a viable option over an arthrodesis is now available for patients with end-stage ankle arthritis. When compared with an ankle arthroplasty, recent reports suggest the ankle arthrodesis has poor long-term outcomes (20 years+) and can experience short- and long-term complications. Proper training, strict patient selection, and proper implant contribute to a successful outcome. As advances continue to be made in both implant design and surgical technique, the benefits of a TAR appears to provide the foot and ankle surgeon a good alternative for the appropriate patient.