Midterm Results of the Salto Talaris Total Ankle Arthroplasty

Risk Factors for Failure of Total Ankle Arthroplasty With a Minimum Five Years of Follow-up

BACKGROUND:

As the popularity of total ankle arthroplasty (TAA) increases and indications expand, surgeons require a better understanding of which patient factors are associated with implant failure. In this study, we aimed to use a large total ankle database to identify independent risk factors for implant failure at mid- to long-term follow-up.

METHODS:

A prospectively collected database was used to identify all patients who underwent primary TAA with a minimum 5 years' follow-up. The primary outcome was revision, defined as removal of one or both metal components; failures due to infection were excluded. Patient and clinical factors analyzed included age, sex, body mass index (BMI), smoking status, presence of diabetes, indication for TAA, implant, tourniquet time, and presence of ipsilateral hindfoot fusion. Preoperative coronal deformity and sagittal talar translation were assessed, as were postoperative coronal and sagittal tibial component alignment. Univariable and multivariable analyses were performed to identify predictors of implant failure. After excluding 5 ankles that failed because of deep infection, 533 ankles with a mean 7 (range, 5-11) years of follow-up met the inclusion criteria. Four implants were used: INBONE I, INBONE II, STAR, and Salto-Talaris.

RESULTS:

Thirty-four ankles (6.4%) were revised or removed a mean 4 (range, 1-9) years postoperatively. The only independent predictors of failure were the INBONE I prosthesis and ipsilateral hindfoot fusion ( P = .006 and P = .023, respectively).

CONCLUSIONS:

This is among the largest studies to analyze the relationship between TAA failure rates and multiple different patient, operative, and radiographic factors. Of note, age, BMI, and amount of deformity were not associated with higher failure rates. Only patients with ipsilateral hindfoot fusion or who received the INBONE I prosthesis were at significantly higher risk of implant failure.

LEVEL OF EVIDENCE:

Level III, retrospective cohort study.

Clinical and Radiological Outcomes of Transfibular Total Ankle Arthroplasty

BACKGROUND:

Ankle arthritis is a highly limiting pathology that causes pain and functional limitation with subsequent deterioration of quality of life. With recent advances in surgical instrumentation and techniques, prosthetic replacement of the ankle has proven to be a valid alternative to arthrodesis with comparable outcomes. The purpose of this study was to evaluate clinical and radiological findings in a transfibular total ankle replacement with follow-up of at least 2 years.

METHODS:

This prospective study included 89 patients who underwent transfibular total ankle arthroplasty from May 2013 to February 2016. The mean age was 53.2 ± 13.5 years. All patients were followed for at least 24 months postoperatively with an average follow-up of 42.0 ± 23.5 months. Patients were assessed clinically and radiographically preoperatively and at 6, 12, and 24 months postoperatively.

RESULTS:

At 24 months postoperatively, patients demonstrated statistically significant improvement in the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle Hindfoot Score from 33.8 ± 14.3 to 88.5 ± 6.6 ( P < .001), visual analog scale (VAS) from 80.5 ± 17.0 to 14.1 ± 9.2 ( P < .001), and Short Form-12 Physical and Mental Composite Scores from 29.9 ± 6.7 and 43.3 ± 8.6 to 47.0 ± 7.6 and 53.3 ± 8.1, respectively ( P < .001). In addition, ankle dorsiflexion and plantarflexion improved from 6.2 ± 5.5 and 9.6 ± 5.8 degrees to 24.2 ± 7.9 and 18.1 ± 7.6 degrees, respectively ( P < .001). Radiographically, patients demonstrated maintained neutral alignment of the ankle at 24 months. No patient demonstrated any radiographic evidence of tibial or talar lucency at final follow-up. Seven patients underwent reoperation for removal of symptomatic hardware (6 fibular plates, 1 syndesmotic screw); 2 patients experienced delayed wound healing. The first one was treated with plate removal and flap coverage. The second one required fibular plate removal. One patient developed a postoperative prosthetic infection requiring operative debridement, removal of implants, and placement of an antibiotic spacer.

CONCLUSION:

This study found that transfibular total ankle replacement was a safe and effective option for patients with ankle arthritis resulting in improvements in patient-reported outcomes, range of motion, and radiographic parameters. However, further studies are required to determine the mid- and long-term performance of these implants.

LEVEL OF EVIDENCE:

Level IV, case series.

Increased Early Revision Rate With the INFINITY Total Ankle Prosthesis

BACKGROUND:

A number of new 2-component total ankle arthroplasty systems that emphasize minimal bone resection have been introduced for which few clinical outcomes reports are available. Our aim was to identify the rate of early revision among patients receiving the 2-component INFINITY prosthesis.

METHODS:

Patients from 2 prospectively collected databases at the authors' institution were screened for inclusion in the present study. All patients who underwent a primary total ankle arthroplasty (TAA) with the INFINITY prosthesis and who were at least 1 year postoperative were included. A total of 159 ankles with a mean 20 months of follow up (range, 12-37) met these criteria. All surgeries were performed by 1 of 2 orthopedic foot and ankle surgeons with extensive experience in TAA. The primary outcome was the need for revision surgery, defined as removal of 1 or both metal components. Peri-implant lucency at most recent follow-up was a secondary outcome. Weightbearing radiographs at most recent follow-up were graded for lucency independently by 2 reviewers.

RESULTS:

Sixteen ankles (10%) underwent revision at a mean 13 months postoperatively. The most common reasons for revision were symptomatic tibial component loosening and deep infection (6 patients each, 3.8%). Of the 108 ankles with retained components and at least 1 year of radiographic follow-up, 8 (7.4%) had global lucency around the tibial component suggestive of loosening at most recent follow-up.

CONCLUSIONS:

Our initial review of patients undergoing TAA with this new 2-component prosthesis demonstrates an elevated early revision rate due to tibial component loosening compared to other implant systems.

LEVEL OF EVIDENCE:

Level IV, case series.

Lower Bone Density on Preoperative Computed Tomography Predicts Periprosthetic Fracture Risk in Total Ankle Arthroplasty

BACKGROUND:

The effect of bone mineral density (BMD) on outcomes from total ankle arthroplasty (TAA) has not been studied. BMD can be estimated by measuring Hounsfield units (HU) on standard computed tomography (CT), which is frequently performed prior to TAA. We aimed to identify whether tibial and talar HU measured from preoperative CT scans were associated with periprosthetic fracture or revision risk in patients undergoing TAA.

METHODS:

A prospectively collected database was used to retrospectively screen all patients undergoing primary TAA. Only patients with a preoperative CT within 1 year of surgery were included. Primary outcomes were periprosthetic fracture and prosthetic revision. HU were measured on axial CT cuts in the distal tibia and talus. Additional patient factors analyzed included age, sex, weight, body mass index (BMI), tobacco use, presence of rheumatoid arthritis, and preoperative deformity. A total of 198 ankles were included, with a mean 2.4 years of follow-up.

RESULTS:

There were 7 intraoperative and 9 postoperative periprosthetic fractures (3.5% and 4.5%, respectively). Seven patients (3.5%) underwent prosthetic removal or revision. Lower tibial and talar HU, lower weight, and lower BMI were associated with periprosthetic fractures ( P < .05). After controlling for age, sex, and weight, only tibial HU was significantly associated with periprosthetic fracture ( P = .018). All intraoperative fractures occurred in patients with tibial HU less than 200. None of the patient factors analyzed were associated with revision.

CONCLUSIONS:

Lower tibial HU on preoperative CT was strongly associated with periprosthetic fracture risk with TAA. In patients with tibial HU less than 200, surgeons may consider prophylactic internal fixation of the medial malleolus.

LEVEL OF EVIDENCE:

Level III, retrospective cohort study.

Management of Posttraumatic Ankle Arthritis: Literature Review

PURPOSE OF REVIEW

Trauma is the principle cause of osteoarthritis in the ankle, which is associated with significant morbidity. This review highlights the current literature for the purpose of bringing the reader up-to-date on the management of posttraumatic ankle arthritis, describing treatment efficacy, indications, contraindications, and complications.

RECENT FINDINGS

Recent studies on osteoarthritis have demonstrated variability among anatomic locations regarding the mechanisms and rates of development for posttraumatic osteoarthritis, which are attributed to newly discovered biological differences intrinsic to each joint. Regarding surgical management of posttraumatic ankle arthritis, osteochondral allograft transplantation of the talus, and supramalleolar osteotomies have demonstrated promising results. Additionally, the outpatient setting was found to be appropriate for managing pain following total ankle arthroplasty, associated with low complication rates and no readmission. Management for posttraumatic ankle arthritis is generally progressive. Initial treatment entails nonpharmacologic options with surgery reserved for posttraumatic ankle arthritis refractory to conservative treatment. Patient demographics and lifestyles should be carefully considered when formulating a management strategy, as outcomes are dependent upon the satisfaction of each set of respective criteria. Ultimately, the management of posttraumatic ankle arthritis should be individualized to satisfy the needs and desires, which are specific to each patient.

Outcomes of Acute Hematogenous Periprosthetic Joint Infection in Total Ankle Arthroplasty Treated With Irrigation, Debridement, and Polyethylene Exchange

BACKGROUND

Acute hematogenous periprosthetic joint infection (PJI) is defined in the literature as infection diagnosed and treated within 2 to 4 weeks from the onset of symptoms. In total hip and knee arthroplasty, irrigation and debridement (I&D) and polyethylene exchange with component retention has been studied extensively. However, there is minimal literature evaluating this treatment method for PJI in total ankle arthroplasty (TAA). The purpose of this study was to evaluate both the clinical and patient-reported outcomes and survivorship of TAA acute hematogenous PJIs treated with I&D and polyethylene exchange.

METHODS

A single-center, retrospective chart review of prospectively collected data in patients with TAA PJI who subsequently underwent I&D and polyethylene exchange with retention of metal components was conducted. The primary outcome was failure rate of I&D and polyethylene exchange, where failure was defined as subsequent removal of all components and 2-stage revision or arthrodesis. Patient-reported outcomes collected before primary arthroplasty, after primary arthroplasty, and after polyethylene exchange were also analyzed.

RESULTS

We identified 14 patients with acute hematogenous PJI who underwent I&D and polyethylene exchange with retention of metal components. The mean time from primary TAA to symptoms was 43 months (range 1-147 months). The average time from onset of symptoms to I&D and polyethylene exchange was 11.4 ± 5.6 days. The mean follow-up after this surgery was 2.8 ± 1.5 years. The long-term failure rate was 54%. The most common bacteria isolated in patients who failed was methicillin-resistant Staphylococcus aureus (MRSA). The most common bacteria isolated in patients who retained their implants was methicillin-sensitive Staphylococcus aureus (MSSA). Visual analog scale (VAS), Short Musculoskeletal Function Assessment (SMFA), Short Form-36 (SF-36), and American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scale showed significant improvement when compared to preoperative scores in patients who retained their implants both after primary and after I&D and polyethylene exchange.

CONCLUSIONS

I&D and polyethylene exchange with retention of metal components has a long-term survivorship comparable to those reported in the total knee and total hip arthroplasty literature. Patient-reported outcomes after I&D and polyethylene exchange were comparable to those collected after primary arthroplasty in those patients who ultimately retained their implants. Two variables in this cohort that were associated with I&D and polyethylene exchange failure include time the patient was symptomatic prior to I&D as well as organism isolated on culture. With a failure rate of 54%, the authors recommend thorough evaluation on a case-by-case basis prior to indicating a patient for single-stage I&D with polyethylene exchange.

LEVELS OF EVIDENCE

Level IV, case series.

Obesity in Elective Foot and Ankle Surgery

Obesity is a global health problem with significant economic and health consequences. There is very little literature in regards to obesity and its effect on foot and ankle surgery, and to the author's knowledge, there has been no consolidated review on this subject to date. The purpose of this article is to provide a comprehensive review as it pertains to foot and ankle surgery, with hopes of improving surgeon decision making, mitigating risk, and providing better outcomes for patients. A better understanding of the effects of obesity also allows for improved prognostic performance.

Midterm Outcomes of a Fixed-Bearing Total Ankle Arthroplasty With Deformity Analysis

BACKGROUND

We present our results with an INBONE I (Wright Medical, Memphis, TN) prosthesis that have a minimum of 4 to 10 years of follow-up and include a preoperative deformity analysis on outcomes.

METHODS

A consecutive series of 149 patients, from 2007 to 2011, at a single institution were enrolled. Pain and patient-reported function were assessed preoperatively and at yearly follow-ups. We analyzed the data for complications, reoperations, and failures (defined as undergoing revision for exchange or removal of one or both metallic components for any reason). Patients were also grouped according to coronal plane tibiotalar alignment; either ≥10 degrees or <10 degrees, and these outcomes were compared. Our follow-up ranged from 48 to 113 months (average 5.9 years).

RESULTS

There was significant improvement ( P < .05) in the visual analog scale for pain, American Orthopaedic Foot & Ankle Society hindfoot scale, Short Musculoskeletal Function Assessment, and Short Form 36-Item Health Survey scores at most recent follow-up. There were 14 implant failures with overall survivorship of 90.6% (135/149). Reasons for failure included cysts/loosening (7), talar subsidence (4), fractured component (1), impingement pain (1), and infection (1). Seventy-two patients (48.3%) with preoperative coronal plane deformity of ≥10 degrees varus or valgus were compared to 78 patients (51.7%) with <10 degrees deformity. There was no difference in patient outcome scores or revision rates between these patient groups. There was a statistically significant difference ( P = .039) in reoperation rates among patients with ≥10 degrees deformity (22.2%) compared to those without such a deformity (37.7%) Conclusion: Patients who underwent INBONE I fixed-bearing total ankle arthroplasty demonstrated significant improvement in outcomes at a mean of 5.9 years. Catastrophic talar component collapse did occur (2.7% of cases), but relatively rarely. The patients with preoperative coronal plane tibiotalar deformity had similar pain relief, function, and need for revision of implant components. Despite the presumed shortcomings of the INBONE I's design, this implant showed promising results, with or without deformity, at midterm follow-up with survivorship of 90.6%.

LEVEL OF EVIDENCE

Level III, comparative study.