UNCEMENTED STAR TOTAL ANKLE PROSTHESES

Sports Activity with Ankle Osteoarthritis and Total Ankle Arthroplasty

Background/Objectives: The interest in performing total ankle arthroplasty (TAA) to address end-stage ankle osteoarthritis (OA) is continuously growing. Sports activity plays an important role in our world. The literature is sparse regarding return-to-sports activity following TAA. The levels and types of sports in TAA are rarely reported. The purpose of this prospective case series study is to investigate sports activity in ankle osteoarthritis (OA) and TAA in terms of rate, frequency, type, and clinical outcomes with a minimum 2 years of follow-up after surgery. Methods: A total of 103 patients (105 implants, 52 female, and 51 male), mean age 60.5 years (range, 23-84 years) with end-stage ankle OA were treated using a three-component, uncemented, mobile-bearing VANTAGE Total Ankle System. The mean follow-up was 2.9 years (range, 2-5 years). Visual Analogic Scale Pain Score (VAS, 0-10 points), Ankle Dorsiflexion/Plantarflexion (DF/PF) range of motion (ROM; degrees), functional American Orthopaedic Foot and Ankle Society (AOFAS) Ankle/Hindfoot Score (0-100 points), Subjective Patients' Satisfaction Score (0-10 points), Sports Activity Rate, Sports Frequency Score, and sports type were assessed. Results: The mean preoperative VAS Pain Score was 6.7 points (range, 3-10 points) and 0.2 points for postoperative (range, 0-3 points) (p < 0.001). The mean DF/PF ROM was 24.9° preoperative (range, 0-60°) and 52.9° postoperative (range, 15-85°) (p < 0.001). The mean preoperative functional AOFAS Ankle/Hindfoot Score was 39.5 points (range, 4-57 points) and 97.8 points for postoperative (range, 75-100 points) (p < 0.001). The mean postoperative Subjective Patients' Satisfaction Score was 9.7 points (range, 7-10 points). The preoperative Sports Activity Rate was 31.1%, with 85.4% for postoperative (p < 0.001). All the groups exhibited substantial Sports Frequency Score increases (p < 0.001). The most practised sports were hiking, biking, fitness, and swimming. Conclusions: total ankle arthroplasty (TAA) is an effective treatment for end-stage ankle OA. TAA facilitates a noteworthy increase in sports activity. This research offers important sports insights to patients with ankle OA and TAA.

Post-Traumatic Arthritis of the Knee and Ankle

Post-traumatic osteoarthritis (PTOA) occurs following injury to joints. It accounts for approximately 12% of osteoarthritis and has far-reaching effects on individual patients and social/health care systems. Present work focuses on evaluating the role of the post-traumatic inflammatory response in the development and progression of the disease. As there is minimal evidence to suggest the capacity of cartilage to undergo self-healing, most of this work focuses strictly on the avoidance or prevention of PTOA as opposed to treatment solutions following its onset. Ongoing and future investigations may reveal therapeutic targets for possible intervention and ultimately the prophylaxis of PTOA development.

Bone grafting for periprosthetic bone cysts following total ankle arthroplasty

Aims

The purpose of this study was to assess the success rate and functional outcomes of bone grafting for periprosthetic bone cysts following total ankle arthroplasty (TAA). Additionally, we evaluated the rate of graft incorporation and identified associated predisposing factors using CT scan.

Methods

We reviewed a total of 37 ankles (34 patients) that had undergone bone grafting for periprosthetic bone cysts. A CT scan was performed one year after bone grafting to check the status of graft incorporation. For accurate analysis of cyst volumes and their postoperative changes, 3D-reconstructed CT scan processed with 3D software was used. For functional outcomes, variables such as the Ankle Osteoarthritis Scale score and the visual analogue scale for pain were measured.

Results

Out of 37 ankles, graft incorporation was successful in 30 cases. Among the remaining seven cases, four (10.8%) exhibited cyst re-progression, so secondary bone grafting was needed. After secondary bone grafting, no further progression has been noted, resulting in an overall 91.9% success rate (34 of 37) at a mean follow-up period of 47.5 months (24 to 120). The remaining three cases (8.1%) showed implant loosening, so tibiotalocalcaneal arthrodesis was performed. Functional outcomes were also improved after bone grafting in all variables at the latest follow-up (p < 0.05). The mean incorporation rate of the grafts according to the location of the cysts was 84.8% (55.2% to 96.1%) at the medial malleolus, 65.1% (27.6% to 97.1%) at the tibia, and 81.2% (42.8% to 98.7%) at the talus. Smoking was identified as a significant predisposing factor adversely affecting graft incorporation (p = 0.001).

Conclusion

Bone grafting for periprosthetic bone cysts following primary TAA is a reliable procedure with a satisfactory success rate and functional outcomes. Regular follow-up, including CT scan, is important for the detection of cyst re-progression to prevent implant loosening after bone grafting.

STAR® total ankle replacements with BONIT® coating: A prospective 2-17 year follow-up study of 474 ankles from a single center

BACKGROUND

Different coatings of the metal implants of STAR prostheses have been used since 1999. In Europe metal implants with a double calcium-phosphate coating (BONIT) on a titanium sprayed surface have been available since 1999.

METHODS

We present a 2-17 year follow-up of a consecutive series from a single center with 474 STAR ankle replacements where the BONIT type of coating has been used.

RESULTS

55 prostheses (12%) have been revised, the majority of them due to fracture of the mobile bearing. 22 prostheses (5%) have been converted to an arthrodesis. Analysis of survival of the specific components showed an estimated 10-year survival rate of the tibia component, talus component and polyethylene mobile bearing of 99%, 98% and 84%, respectively. The corresponding estimated 15-year survival was 98%, 98% and 74%, respectively.

CONCLUSION

This study showed an extraordinary high survival rate of the metal implants.

LEVEL OF EVIDENCE

Level III, prospective cohort series.

Development and validation of a clinical tool to semi-automatic measure three-dimensional TAR alignment on two-dimensional radiographs

BACKGROUND

Malalignment is often postulated as an important reason for the high failure rate of total ankle replacements (TARs). The correlation between TAR malalignment and clinical outcome, however, is not fully understood. Improving and expanding radiographic TAR alignment measurements in the clinic might lead to a better insight into the correlation between malalignment and the clinical outcome. This study aims to develop and validate a tool to semi-automatic measure TAR alignment, and to improve alignment measurements on radiographs in the clinic.

METHODS

A tool to semi-automatically measure TAR alignment on anteroposterior and lateral radiographs was developed in MATLAB. Using the principle of edge contouring and the perpendicular relationship between the anteroposterior and lateral radiographs, the exact configuration of the TAR components can be found. Two observers validated the tool by measuring TAR alignment of ten patients using the tool. The Intraclass Coefficient (ICC) was calculated to assess the reliability of the developed method. The results obtained by the tool were compared to clinical results during radiographic follow-up in the past, and the accuracy of both methods was calculated using three-dimensional CT data.

RESULTS

The tool showed an accuracy of 76% compared to 71% for the method used during follow-up. ICC values were 0.94 (p < 0.01) and higher for both inter-and intra-observer reliability.

CONCLUSIONS

The tool presents a reproducible method to measure TAR alignment parameters. Three-dimensional alignment parameters are obtained from two-dimensional radiographs, and as the tool can be applied to most TAR designs, it offers a valuable addition in the clinic and for research purposes.

Total Ankle Arthroplasty for Posttraumatic Fracture Versus Primary Osteoarthritis: An Analysis of Complications, Revisions, and Prosthesis Survival

BACKGROUND

Most outcome studies of total ankle arthroplasty (TAA) do not discriminate by arthritis etiology. The primary purpose of this study was to compare the complications of TAA between posttraumatic fracture osteoarthritis (fracture PTOA) and primary osteoarthritis (POA).

METHODS

Ninety-nine patients who underwent TAA were retrospectively evaluated with a mean follow-up of 3.2 years (range 2 to 7.6 years). 44 patients (44%) had a diagnosis of POA while 55 patients (56%) had a diagnosis of fracture PTOA (40 malleolar fractures [73%], 14 pilon fractures[26%], and 1 talar fracture [1%]). Patient demographics, preoperative coronal plane alignment, postoperative complications, and revision surgery data were collected. Categorical variables were compared with chi square and Fisher exact tests and means with the Student t-test. Survival was assessed with Kaplan-Meier and log-rank analyses.

RESULTS

A higher overall complication rate was associated with fracture PTOA (53%) compared with POA (30%) (P = 0.04). No difference was observed in rates of any specific complication by etiology. Survival, defined as revision surgery with TAA prosthesis retention, was comparable between POA (91%) and fracture PTOA (87%) (P = 0.54). When defined as failure requiring prosthesis explant, POA demonstrated significantly greater survival (100%) as compared with fracture PTOA (89%) (P = 0.03). A higher rate of talar implant subsidence and loosening was noted in TAA with prior pilon (29%) as compared to malleolar fractures (8%) that was not statistically significant (P = 0.07). Fracture PTOA was associated with preoperative valgus deformity (P = 0.04). Compared with varus and normal alignment, preoperative valgus deformity was associated with the need for any revision surgery (P = 0.01) and prosthesis explant (P = 0.02).

CONCLUSIONS

Compared with POA, fracture PTOA was associated with a markedly higher complication rate after TAA and was at higher risk of failure requiring prosthesis explant. Fracture PTOA was markedly associated with preoperative valgus malalignment, an identified risk factor in this series for revision surgery and prosthesis explant. Pilon fractures may represent a group at risk of complications related to talar implant subsidence and loosening compared with malleolar fractures and thus warrants additional investigation.

LEVEL OF EVIDENCE

III.

Total Ankle Replacement Outcome in Patients With Inflammatory Versus Noninflammatory Arthritis: A Systematic Review and Meta-analysis

BACKGROUND

The decision regarding total ankle replacement (TAR) is challenging in patients with inflammatory arthritis (IA) regarding more inferior bone quality, large bone cysts, and increased risk of infections. This systematic review and meta-analysis aimed to compare the functional outcome, revision rate, complication rate, and survival rate of TAR between IA (including rheumatoid arthritis [RA]) and noninflammatory arthritis (NIA) (primary and posttraumatic).

METHODS

After reviewing the full texts, 30 articles fulfilled all inclusion criteria from 1985 until 2021, comparing TAR results. The eligible studies included 5508 patients, of whom 1565 patients had IA and 3943 patients had NIA. At the time of surgery, the average age was 58 years in the IA group and 63 in the NIA group. The average follow-up was 67.2 months in the IA group and 67 months in the NIA group. The outcome measures were the American Orthopaedic Foot and Ankle Society (AOFAS) score and the rate of complications, revisions, and survival.

RESULTS

The mean final AOFAS score was 82 (95% confidence interval [CI]: 78-86) in the IA group and 83 (95% CI: 78-88) in the NIA group, with no significant difference. There was no significant difference in the mean preoperative to postoperative AOFAS score change between the IA and the NIA. The complication rate was 16% (95% CI: 9%-27%) in the IA group and 15% (95% CI: 8%-27%) in the NIA group with no significant difference. The revision rate was 12% (95% CI: 10%-15%) in the IA group and 13% (95% CI: 10%-18%) in the NIA group, which was significant (P = .04). There was no significant difference in the survival rate between IA and NIA.

CONCLUSION

Total ankle replacement is a safe procedure in inflammatory ankle arthritis, specifically in RA patients with relatively minor and major complications close to other reasons for ankle replacement.

LEVELS OF EVIDENCE

Level IV: prognostic.

Short-Term Outcomes of Primary Total Ankle Arthroplasty in Octogenarians: A National Database Analysis

BACKGROUND

Total ankle arthroplasty (TAA) is an increasingly popular option for end-stage ankle arthritis. Americans over the age of 80 years grew to 16.7 million in 2010, but there are scarce data assessing the outcomes of octogenarians undergoing TAA. This study evaluated (1) perioperative factors, (2) 30-day postoperative complications compared to a nonoctogenarian cohort, and (3) independent risk factors for adverse outcomes.

METHODS

A national database registry was queried for patients who had undergone primary TAA. This yielded 1113 patients, under (n = 1059) and over (n = 54) age 80 years. Demographics and perioperative data were compared using Fisher's exact, χ², and independent-samples t tests. Logistic and Poisson regressions were used to calculate odds ratio (OR) of complications and independent risk factors.

RESULTS

The octogenarian cohort had longer in-hospital length of stay (1.9 vs 2.5 days, P < .0001). Octogenarians were not significantly more likely to develop any complication (OR = 1.32; 95% confidence interval = 0.29-6.04; P = .722), or increased number of complications (OR = 1.18; 95% CI = 0.27-5.18; P = .820). Octogenarians had significantly increased risk of being discharged to rehab/skilled nursing (OR = 6.60; 95% CI = 2.16-20.15; P < .001) instead of home.

CONCLUSION

Although the elderly population may carry inherent risk factors, octogenarians do not present an increased risk of short-term complications following TAA.

LEVELS OF EVIDENCE

Therapeutic, Level III: Retrospective cohort study.

Ten-year revision rates of contemporary total ankle arthroplasties equal 22%. A meta-analysis

BACKGROUND

The National Institute for Health and Care Excellence criterion for hip replacements is a (projected) revision rate of less than 5% after 10 years. No such criterion is available for ankle prostheses. The objective of the current study is to compare survival rates of contemporary primary ankle prostheses to the hip-benchmark.

METHODS

The PRISMA methodology was used. Eligible for inclusion were clinical studies reporting revision rates of currently available primary total ankle prostheses. Data was extracted using preconstructed forms. The total and prosthesis-specific annual revision rate was calculated.

RESULTS

Fifty-seven articles of eight different ankle prostheses were included (n = 5371), totaling 513 revisions at an average 4.6 years of follow-up. An annual revision rate of 2.2 was found (i.e. an expected revision rate of 22% at 10 years).

CONCLUSIONS

The expected 10-year revision rate of contemporary ankle prostheses is lower than the current benchmark for hip prostheses.

The Most-Cited Ankle Arthroplasty Implant Articles

Background:

Citation analysis is a useful way of evaluating the impact, importance, and merit of articles within a medical specialty. Our study identified and analyzed the most-cited articles on ankle arthroplasty implants to evaluate their importance in the field of ankle arthroplasty research.

Methods:

Using the keywords “ankle arthroplasty” and “ankle replacement” and the search period 1970-2021, we found 3728 articles on ankle arthroplasty implants in the Scopus, Web of Science, and MEDLINE/PubMed databases. We included original articles, reviews, clinical trials, and case reports in the study. We retrieved the 50 most-cited articles published during the time frame and then screened them for studies of specific ankle arthroplasty implants and their postoperative outcomes. We also recorded and analyzed the articles’ subjects, authorship, journals, countries of origin, and years of publication.

Results:

The 50 most-cited articles were published between 1983 and 2014, with the majority (33) published between 2000 and 2010. They generated 9012 citations in the literature. The most-cited study accounted for 497 citations; the mean number of citations per article was 180.24 ± 76.24. Twenty-three (46%) of the articles addressed postoperative outcomes following a specific type of arthroplasty implant. Arthroplasty implant studies accounted for 4726 citations, or 52.4% of the citations of the 50 articles. The most frequently studied arthroplasty implant was STAR (15), followed by Agility (7), Buechel Pappas (5), and Salto (4). STAR accounted for 3311 citations, or 37% of the total citations of the 50 articles.

Conclusion:

Ankle arthroplasty research has made great progress in the past 2 decades, particularly in the area of postoperative outcomes of specific ankle implants, but continued research and publication on additional arthroplasty implants should become a priority.

Level of Evidence:

Level V, Review Article.

Analysis of 408 Total Ankle Arthroplasty Adverse Events Reported to the US Food and Drug Administration From 2015 to 2018

Background. Total ankle arthroplasty (TAA) use has increased with newer generation implants. Current reports in the literature regarding complications use data extracted from high-volume centers. The types of complications experienced by lower-volume centers may not be reflected in these reports. The purpose of this study was to determine a comprehensive TAA adverse event profile from a mandatory-reporting regulatory database. Methods. The US Food and Drug Administration's Manufacturer and User Facility Device Experience (MAUDE) database was reviewed from 2015 to 2018 to determine reported adverse events for approved implants. Results. Among 408 unique TAA device failures, the most common modes of failure were component loosening (17.9%), intraoperative guide or jig error (15.4%), infection (13.7%), and cyst formation (12.7%). In addition, the percentage distribution of adverse event failure types differed among implants. Conclusion. The MAUDE database is a publicly available method that requires mandatory reporting of approved device adverse events. Using this report, we found general agreement in types of complications reported in the literature, although there were some differences, as well as differences between implants. These data may more accurately reflect a comprehensive profile of TAA complications as data were taken from a database of all device users rather than only high-volume centers.Levels of Evidence: NA.

Short- to Midterm Follow-up of Cemented Total Ankle Replacement Using the INBONE II: A Retrospective Chart Review

Background: Total ankle arthroplasty is a viable option for the treatment of end stage ankle arthritis. The purpose of this study is to report on the mid-term results with a cemented total ankle prosthesis, the Inbone™ II implant over a 5 year period. Methods: A retrospective, single-center chart and radiographic review of all patients with end stage ankle arthritis treated with Inbone™ II TAR) as the primary index procedure from 12/1/2012 to 3/1/2017. Clinical data were evaluated at 3 month, 6 month, 1 year and subsequent intervals for the study period. Preoperative diagnosis, pertinent patient demographics adjunctive procedures, implant associated complications, subsequent surgeries, and revisions were recorded. Results: 121 total ankles met our inclusion criteria. Patients had an INBONE™ II TAR implant placed with bone cement with a minimum of a 12 months follow up. Average age was 62.88 (range, 32-87) years, average body mass index was 32.74 (range, 21.8-56.04) kg/m2 and average follow up was 28.51(range, 12-69) months. Using the COFAS complication classification there were 14 minor, 11 moderate, and 5 major complications. 6/121 (5.0%) revisions which included: polyethylene exchange, device explant/fusion, and antibiotic spacer in situ. No complications over the course of this study ended in amputation. Conclusion: Total Ankle Arthroplasty utilizing the cemented INBONE™ II yielded good midterm results with regards to minor, moderate, and major complications. Rate of revision 6/121 (5.0%) was within the reported range with only 5 patients converted to fusion during the study period resulting in a 95% survivability at mid-term follow up.Levels of Evidence: Level IV: Retrospective case series.

The effect of ankle osteoarthritis and total ankle arthroplasty on center of pressure position

Total ankle arthroplasty (TAA) is a common surgical approach for patients with end-stage ankle osteoarthritis (OA). However, very little is known about the path of the center of pressure (COP) of the foot, and thus important aspects of load transfer, muscle mechanical advantage, and balance, in patients before or after surgery. The objective of this study was to trace the pathway of the COP under the foot in patients with symptomatic ankle OA, comparing asymmetry between affected and unaffected limbs. From force plate data, proximodistal and mediolateral positions of the COP beneath the foot were calculated and compared for the affected and unaffected foot in patients with unilateral ankle OA (N = 93) before and after TAA. Gender and age at surgery had little or no effect in this study. Patients with ankle OA had minimal COP position asymmetry before surgery, and this asymmetry was reduced following surgery. Before surgery, patients had a slower walking speed and a shorter path of the COP which began relatively distal to the heel and ended relatively proximal to the hallux. TAA increased the proximodistal distance the COP traveled under both the unaffected and affected foot, a pattern that was maintained for over 2-year postsurgery. TAA allows patients with ankle OA to maintain a longer COP path than they had before surgery on both sides that is closer to that reported for unaffected individuals, extending effectively from the heel to the hallux, potentially improving pedal mechanics.

Should 15° of valgus coronal-plane deformity be the upper limit for a total ankle arthroplasty?

AIMS

Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°.

METHODS

A matched cohort of patients similar for demographics and components used but differing in preoperative coronal-plane tibiotalar valgus deformity ≥ 15° (valgus, n = 50; 52% male, mean age 65.8 years (SD 10.3), mean body mass index (BMI) 29.4 (SD 5.2)) or < 15° (control, n = 50; 58% male, mean age 65.6 years (SD 9.8), mean BMI 28.7 (SD 4.2)), underwent TAA by one surgeon. Preoperative and postoperative radiographs, Ankle Osteoarthritis Scale (AOS) pain and disability and 36-item Short Form Health Survey (SF-36) version 2 scores were collected prospectively. Ancillary procedures, secondary procedures, and complications were recorded.

RESULTS

At mean 5.1 years follow-up (SD 2.6) (valgus) and 6.6 years (SD 3.3) (controls), mean AOS scores decreased and SF-36 scores increased significantly in both groups. Improvements in scores were similar for both groups - AOS pain: valgus, mean 26.2 points (SD 24.2), controls, mean 22.3 points (SD 26.4); AOS disability: valgus, mean 41.2 points (SD 25.6); controls, mean 34.6 points (SD 24.3); and SF-36 PCS: valgus, mean 9.1 points (SD 14.1), controls, mean 7.4 points (SD 9.8). Valgus ankles underwent more ancillary procedures during TAA (40 (80%) vs 13 (26%)) and more secondary procedures postoperatively (18 (36%) vs 7 (14%)) than controls. Tibiotalar deformity improved significantly (p < 0.001) towards a normal weightbearing axis in valgus ankles. Three valgus and four control ankles required subsequent fusion, including two for deep infections (one in each group).

CONCLUSION

Satisfactory mid-term results were achieved in patients with preoperative valgus malalignment ≥ 15°, but they required more adjunctive procedures during and after TAA. Valgus coronal-plane deformity ≥ 15° is not an absolute contraindication for TAA if associated deformities are addressed. Cite this article: Bone Joint J 2020;102-B(12):1689-1696.

Compensatory Motion of the Subtalar Joint Following Tibiotalar Arthrodesis: An in Vivo Dual-Fluoroscopy Imaging Study

BACKGROUND

Tibiotalar arthrodesis is a common treatment for end-stage tibiotalar osteoarthritis, and is associated with a long-term risk of concomitant subtalar osteoarthritis. It has been clinically hypothesized that subtalar osteoarthritis following tibiotalar arthrodesis is the product of compensatory subtalar joint hypermobility. However, in vivo measurements of subtalar joint motion following tibiotalar arthrodesis have not been quantified. Using dual-fluoroscopy motion capture, we tested the hypothesis that the subtalar joint of the limb with a tibiotalar arthrodesis would demonstrate differences in kinematics and increased range of motion compared with the subtalar joint of the contralateral, asymptomatic, untreated ankle.

METHODS

Ten asymptomatic patients who had undergone unilateral tibiotalar arthrodesis at a mean (and standard deviation) of 4.0 ± 1.8 years previously were evaluated during overground walking and a double heel-rise task. The evaluation involved markerless tracking with use of dual fluoroscopy integrated with 3-dimensional computed tomography, which allowed for dynamic measurements of subtalar and tibiotalar dorsiflexion-plantar flexion, inversion-eversion, and internal-external rotation. Range of motion, stance time, swing time, step length, and step width were also measured.

RESULTS

During the early stance phase of walking, the subtalar joint of the limb that had been treated with arthrodesis was plantar flexed (-4.7° ± 3.3°), whereas the subtalar joint of the untreated limb was dorsiflexed (4.6° ± 2.2°). Also, during the early stance phase of walking, eversion of the subtalar joint of the surgically treated limb (0.2° ± 2.3°) was less than that of the untreated limb (4.5° ± 3.2°). During double heel-rise, the treated limb exhibited increased peak subtalar plantar flexion (-7.1° ± 4.1°) compared with the untreated limb (0.2° ± 1.8°).

CONCLUSIONS

A significant increase in subtalar joint plantar flexion was found to be a primary compensation during overground walking and a double heel-rise activity following tibiotalar arthrodesis.

CLINICAL RELEVANCE

Significant subtalar joint plantar flexion compensations appear to occur following tibiotalar arthrodesis. We found an increase in subtalar plantar flexion and considered the potential relationship of this finding with the increased rate of subtalar osteoarthritis that occurs following ankle arthrodesis.

A Systematic Review of Unsystematic Total Ankle Replacement Wear Evaluations

BACKGROUND

Numerous studies have reported the use of laboratory multistation joint simulators to successfully predict wear performance and functionality of hip and knee replacements. In contrast, few studies in the peer-reviewed literature have used joint simulation to quantify the wear performance and functionality of ankle replacements. We performed a systematic review of the literature on joint simulator studies that quantified polyethylene wear in total ankle arthroplasty. In addition to the quantified wear results, the load and motion parameters were identified and compared among the studies.

METHODS

A search was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify articles reporting total ankle replacement polyethylene wear using joint simulators.

RESULTS

Nine studies that used joint simulators and 1 study that used a computer simulation were found. Although all studies used physiological multidirectional motions (i.e., internal/external rotation, plantar flexion/dorsiflexion, anterior/posterior translation), there was large variability among the studies in the magnitudes of these motions. Among these studies, mean non-cross-linked polyethylene wear ranged from 3.3 ± 0.4 to 25.8 ± 3.1 mm per million cycles. In contrast, mean highly cross-linked polyethylene wear ranged from 2.1 ± 0.3 to 3.3 ± 0.4 mm per million cycles. The wide distribution in wear rates was attributable to the highly inconsistent kinematic parameters and loads applied as well as differences in implant design and materials.

CONCLUSIONS

There is a severe lack of clinically applicable data on wear performance of total ankle replacements in the peer-reviewed literature. No universal set of kinematic load parameters has been established. Furthermore, only 2 of the published studies have validated their findings using independently derived data, such as retrieval analysis. These shortcomings make it difficult to compare findings as a function of design parameters and materials, or to draw clinically relevant conclusions from these simulations. More work is required to enhance the predictive capability of in vitro simulations of total ankle replacements.

CLINICAL RELEVANCE

The results of joint wear simulator studies may not accurately represent in vivo wear of total ankle replacements. Joint simulator studies should establish that they are accurately replicating in vivo wear, thus enabling use of their predictive capabilities for new materials and designs.

Role of Postoperative Patient-Reported Outcomes to Predict Ankle Arthroplasty and Arthrodesis Revision

BACKGROUND

Patient-reported outcomes are becoming common for measuring patient-centric outcomes in surgery. However, there is little known about the relationship between postoperatively collected patient-reported outcomes and objective clinical outcomes. The objective of this study was to measure whether postoperative Ankle Osteoarthritis Scale (AOS) values were associated with risk of revision among patients having ankle arthrodesis or total ankle arthroplasty for treatment of symptomatic end-stage ankle arthritis.

METHODS

This is a retrospective analysis of a longitudinal cohort of ankle arthrodesis and total ankle arthroplasty patients. A single center recruited patients between 2003 and 2013 and follow-up was at least 4 years. Patients completed the AOS preoperatively and annually following surgery. An extended Cox regression model incorporating time-varying AOS values was used to model risk of failure. A total of 336 patients and 348 ankles were included, representing 139 ankle arthrodesis procedures and 209 total ankle arthroplasties.

RESULTS

The median follow-up time for revisions was 8.2 years and 46 patients had a revision. Higher values of patients' AOS scores in the postoperative period were associated with a higher likelihood of revision (hazard ratio, 1.04 per 1-point increase; 95% confidence interval, 1.03-1.05). Ankle arthrodesis was associated with a reduced risk of revision compared with ankle fusion (hazard ratio, 0.12; 95% confidence interval, 0.03-0.49).

CONCLUSION

This study showed that persistent pain and poor function after fusion or replacement surgery, as measured by elevated values of the AOS, were associated with higher risk of further surgery.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

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.

Metal artifact reduction MRI for total ankle replacement sagittal balance evaluation

BACKGROUND

Restoration of anatomical relationship between talus and tibia is crucial for longevity of total ankle replacement (TAR). Weight-bearing (WB) radiographs are the standard for evaluating the sagittal balance alignment, but are prone to rotational misalignment and altered measurements. Metal artifact reduction sequence (MARS) MRI allows visualization of periprosthetic landmarks and alignment of the image plane to the true sagittal axis of the implant. The purpose of this study was to compare TAR sagittal balance measurements on MARS MRI and WB radiographs.

METHODS

Twenty-three subjects with TAR [10 men/13 women, age 60 (41-73) years; 13 (3-24) months post-op] underwent MARS MRI and standard lateral WB radiographs. Standardized MARS MR images were aligned to the sagittal talar component axis. Three observers performed sagittal balance alignment measurements twice in an independent, random and blinded fashion. Lateral Talar Station (LTS), tibial axis-to-talus (T-T) ratio and normalized tibial axis-to-lateral-process (T-L) distance were measured. Concordance correlation coefficients (CCC) and intraclass correlation coefficients (ICC) were used for statistical analysis. In addition, mixed effects linear models were employed to assess overall concordance of the two image types.

RESULTS

The intraobserver agreement was excellent for radiographic (CCC=0.96) and MRI (CCC=0.90-0.97) measurements. Interobserver agreements were good-to-excellent with overall slightly higher agreements for MRI (ICC=0.78-0.94) than radiography (ICC=0.78-0.90) measurements. The T-T ratios of radiographs and MRI showed a high degree of concordance, whereas LTS was significantly lower on MRI when compared with radiographs, and T-L distance showed notable disagreement between the two imaging types.

CONCLUSION

Sagittal balance measurements performed on standardized weight-bearing radiographs and standardized MARS MRI demonstrate substantial correlation and similarity. Given its high intra and interobserver agreement, MARS MRI may be helpful for the evaluation of TAR sagittal balance.

LEVEL OF EVIDENCE

Level II - Prospective Comparative Study.

Total ankle arthroplasty incorporating a total talar prosthesis

Aims

Total ankle arthroplasty (TAA) has become the most reliable surgical solution for patients with end-stage arthritis of the ankle. Aseptic loosening of the talar component is the most common complication. A custom-made artificial talus can be used as the talar component in a combined TAA for patients with poor bone stock of the talus. The purpose of this study was to investigate the functional and clinical outcomes of combined TAA.

Patients and Methods

Ten patients (two men, eight women; ten ankles) treated using a combined TAA between 2009 and 2013 were matched for age, gender, and length of follow-up with 12 patients (one man, 11 women; 12 ankles) who underwent a standard TAA. All had end-stage arthritis of the ankle. The combined TAA features a tibial component of the TNK ankle (Kyocera, Kyoto, Japan) and an alumina ceramic artificial talus (Kyocera), designed using individualized CT data. The mean age at the time of surgery in the combined TAA and standard TAA groups was 71 years (61 to 82) and 75 years (62 to 82), respectively. The mean follow-up was 58 months (43 to 81) and 64 months (48 to 88), respectively. The outcome was assessed using the Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale, the Ankle Osteoarthritis Scale (AOS), and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q).

Results

The mean preoperative JSSF score of the combined TAA and standard TAA groups was 44 (sd 11) and 49 (sd 10), respectively. The mean postoperative JSSF scores were 89 (sd 6.1) and 72 (sd 15), respectively. The mean postoperative JSSF score of the combined TAA group was significantly higher (p = 0.0034). The mean preoperative AOS scores for pain and function in the combined TAA and standard TAA groups were 5.8 (sd 3.3) and 5.5 (sd 3.1), and 8.6 (sd 1.3), and 7.1 (sd 2.9), respectively. The mean postoperative AOS scores of pain and function were 2.5 (sd 2.5) and 2.2 (sd 1.9), and 2.5 (sd 3.3) and 3.4 (sd 2.9), respectively. There were no significant differences between the two groups in terms of postoperative AOS scores. The mean postoperative SAFE-Q scores were: for pain, 76 (sd 23) and 70 (sd 23); for physical function, 66 (sd 25) and 55 (sd 27); for social function, 73 (sd 35) and 62 (sd 34); for shoe-related, 73 (sd 19) and 65 (sd 26); and for general health, 78 (sd 28) and 67 (sd 29), respectively. There were no significant differences between the two groups in terms of postoperative SAFE-Q scores.

Conclusion

Combined TAA resulted in better clinical results than standard TAA. Cite this article: Bone Joint J 2019;101-B:443–446.

A Critical Radiographic Analysis of Coronal Plane Deformity Correction Using a 3-Piece Mobile Bearing Ankle Joint Replacement: A Retrospective Study of 25 Patients

Total ankle replacement can be a viable option for patients with end-stage ankle arthritis associated with coronal plane deformity. With proper ankle balancing, a well-aligned ankle implant can be maintained over time and provide successful patient outcomes. The purpose of this study was to evaluate radiographic and subjective outcomes in patients with ankle arthritis along with coronal plane deformity who underwent total ankle arthroplasty with a 3-piece mobile-bearing implant. Our primary inclusion criterion was patients who demonstrated more than 5° of tibiotalar coronal deformity in either varus or valgus direction. Sixty-three consecutive patients who underwent total ankle replacement were reviewed. Of these, 25 (39.7%) met the inclusion criteria. Sixteen (64%) patients had a varus deformity (Group 1) and 9 (36%) had valgus deformity (Group 2) preoperatively. Alignment was evaluated radiographically at 5 different intervals: preoperative, immediate postoperative, and 6, 12, and 36 months postoperative. In patients with varus deformity, the mean tibiotalar angle was 12.6°, 0.8°, 1.0°,1.0°, and 0.8° for preoperative, immediate postoperative, and 6, 12, and 36 months, respectively. The same measurements and intervals for patients with valgus deformity were found to be 10.3°, 1.4°, 1.6°, 1.4°, and 1.4°. A statistically significant difference was observed in preoperative and postoperative coronal plane deformity. This correction was maintained at final follow-up visit. American Orthopaedic Foot and Ankle Society scores and visual analogue scale scores were recorded as well, and statistically significant improvements in preoperative and postoperative scores were found (p < .001). In conclusion, coronal plane deformity correction of the ankle can be accomplished and maintained in total ankle replacement procedures with proper soft tissue balancing and osseous procedures as indicated.

The effect of patient age and diagnosis on the 5-year outcomes of mobile-bearing total ankle replacement

Total Ankle Replacement is an established technique for the management of end-stage ankle arthritis. However, there are few studies focussing on patient-reported outcomes in the medium and long term related to age or arthritis type. We compared demographic data and patient-reported outcomes preoperatively and at five years postoperatively for patients who underwent total ankle replacement with the aim of establishing whether differences exist in outcome depending on patient age or diagnosis. The Foot and Ankle Score (FAOS) and 36-item Short-Form (SF-36) Health Survey were analysed by diagnosis (osteoarthritis, rheumatoid arthritis, post-traumatic arthritis) and age (under or over 60 years). At 5 years, the post-traumatic arthritis group had a significantly higher composite score than the osteoarthritis (p<0.0001) or rheumatoid arthritis groups (p<0.0001). Only the post-traumatic arthritis group experienced a significant increase in composite SF-36 score from baseline (p<0.0001). There was a significant improvement from pre-operatively to 5 years in all three domains of the FAOS and in total scores in both groups (over 60 p<0.0001; 60 and under p=0.0002). There was a significant improvement in composite SF-36 score from pre-operative to 5 years in the patients 60 years or younger at the time of surgery (p=0.0006), but not for the patients over 60. Three patients have been revised (4%), at a mean of 4.8 years following surgery with one patient awaiting revision.

Ankle arthroplasty: A review and summary of results from joint registries and recent studies

Total ankle arthroplasty offers a reasonable alternative to ankle arthrodesis in carefully selected patients.

It is debatable whether rheumatoid arthritis patients have better outcomes compared with those who have ankle arthroplasty for either primary osteoarthritis or post-traumatic arthritis.

Aseptic loosening and infection are the most common complications requiring revision.

It is worth noting that some of the best survival rates are seen in the surgeon-designer case series.

The uncemented mobile or fixed bearing prostheses have better outcomes compared with their older counterparts.

There is no convincing evidence to suggest superiority of one design over another among the currently available prostheses.

Ankle arthroplasty surgery has a steep learning curve; the prosthesis choice should be driven by the surgeon’s training and experience.

Cite this article: EFORT Open Rev 2018;3:391-397. DOI: 10.1302/2058-5241.3.170029

Short-term Clinical and Radiographic Results of the Salto Mobile Total Ankle Prosthesis

BACKGROUND

The mobile-bearing Salto total ankle prosthesis has been reported to have promising outcomes. However, clinical reports on this prosthesis are few, and most have been published by the inventors and disclosed consultants.

METHODS

We retrospectively reviewed 59 patients who received Salto prosthesis unilaterally. The average follow-up was 35.9 (range, 6-56) months. Clinical and radiologic results were evaluated. Clinical results were evaluated according to visual analog scale (VAS), American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, Ankle Osteoarthritis Scale (AOS) pain and disability score, and ankle range of motion (ROM) in dorsiflexion/plantarflexion. In the radiographic evaluation, we measured the tibial angle (TA), talar angle (TAL), tibial slope, and talocalcaneal angle (TCA) on weightbearing radiographs.

RESULTS

By the last follow-up, 7 of 59 patients (11.9%) had undergone reoperation, and 3 of 59 implants (5.1%) had been removed. The prosthesis survival was 94.9% (95% CI, 89.1%-100%). With any reoperation as the endpoint of follow-up, the clinical success rate was 88.1% (95% CI, 79.4%-96.9%). The mean postoperative visual analog scale score, AOFAS ankle-hindfoot score, and Ankle Osteoarthritis Scale pain and disability score improved significantly ( P < .001). The ankle range of motion also improved from preoperative 33.4 ± 16.6 to 40.3 ± 15.5 postoperatively ( P < .001); however, there was no statistically significant change in plantarflexion ( P = .243). Radiolucent areas and osteolysis were found in 28 (47.5%) and 27 (45.8%) patients, respectively. Heterotopic ossification was observed in 13 patients (22.0%).

CONCLUSIONS

In this series, early clinical and radiographic outcomes of this prosthesis were promising. We believe the early radiolucent lines were probably due to the gap at the implant and bone interface, and they disappeared at the time of osseous integration. However, longer follow-up is necessary to determine the long-term durability and survivorship of this implant, particularly given the high incidence of postoperative osteolysis.

LEVEL OF EVIDENCE

Level IV, case series.

Finite element analysis of biomechanical effects of total ankle arthroplasty on the foot

Background

Total ankle arthroplasty is gaining popularity as an alternation to ankle arthrodesis for end-stage ankle arthritis. Owing to the complex anatomical characteristics of the ankle joint, total ankle arthroplasty has higher failure rates. Biomechanical exploration of the effects of total ankle arthroplasty on the foot and ankle is imperative for the precaution of postoperative complications. The objectives of this study are (1) to investigate the biomechanical differences of the foot and ankle between the foot with total ankle arthroplasty and the intact foot and (2) to investigate the performance of the three-component ankle prosthesis.

Methods

To understand the loading environment of the inner foot, comprehensive finite element models of an intact foot and a foot with total ankle arthroplasty were developed to simulate the stance phase of gait. Motion analysis on the model subject was conducted to obtain the boundary and loading conditions. The model was validated through comparison of plantar pressure and joint contact pressure between computational prediction and experimental measurement. A pressure mapping system was used to measure the plantar pressure during balanced standing and walking in the motion analysis experiment, and joint contact pressure at the talonavicular joint was measured in a cadaver foot.

Results

Plantar pressure, stress distribution in bones and implants and joint contact loading in the two models were compared, and motion of the prosthesis was analysed. Compared with the intact foot model, averaged contact pressure at the medial cuneonavicular joint increased by 67.4% at the second-peak instant. The maximum stress in the metatarsal bones increased by 19.8% and 31.3% at the mid-stance and second-peak instants, respectively. Force that was transmitted in three medial columns was 0.33, 0.53 and 1.15 times of body weight, respectively, at the first-peak, mid-stance and second-peak instants. The range of motion of the prosthetic ankle was constrained in the frontal plane. The lateral side of the prosthesis sustained higher loading than the medial side.

Conclusion

Total ankle arthroplasty resulted in great increase of contact pressure at the medial cuneonavicular joint, making it sustain the highest contact pressure among all joints in the foot. The motion of the prosthesis was constrained in the frontal plane, and asymmetric loading was distributed in the bearing component of the ankle prosthesis in the mediolateral direction.

The translational potential of this article

Biomechanical variations resulted from total ankle arthroplasty may contribute to negative postoperative outcomes. The exploration of the biomechanical performance in this study might benefit the surgeons in the determination of surgical protocols to avoid complications. The analysis of the performance of the ankle prosthesis could enhance the knowledge of prosthetic design.

Outcome of ankle arthrodesis and ankle prosthesis: a review of the current status

INTRODUCTION

In advanced stages of ankle osteoarthritis (OA), ankle arthrodesis (AA) or total ankle arthroplasty (TAR) may be necessary. Our purpose is to compare AA and total ankle replacement for the surgical management of end stage ankle OA.

SOURCES OF DATA

We conducted a literature search of PubMed, Medline, CINAHL, Cochrane, Embase and Google Scholar databases using the terms 'ankle' in combination with 'OA', 'arthrodesis', 'arthroplasty', 'joint fusion', 'joint replacement'. Studies where treatment was exclusively total ankle replacement or AA were excluded. Treatment characteristics and outcome parameters (overall postoperative outcome and complication rate) were reviewed.

AREAS OF AGREEMENT

When counseling patients who are considering their options with regard to ankle arthritis treatment, surgeons should determine on an individual basis which procedure is more suitable.

AREAS OF CONTROVERSY

TAR has become an accepted treatment for end-stage OA, but revision rates for TAR are significant higher than for AA (odds ratio 2.28 95% confidence interval [CI], 1.63-3.19; P < 0.0001).

GROWING POINTS

The results of TAA are gradually improving, but the procedure cannot yet be recommended for the routine management of ankle OA.

AREAS TIMELY FOR DEVELOPING RESEARCH

Although there is some evidence to support TAR to conserve ankle motion and offer improved function and decreased pain with high satisfaction rates, revision rates for TAR are significantly higher than revision rates for AA. Proper patient selection should be better addressed in future studies for successful treatment of end-stage ankle OA.

LEVEL OF EVIDENCE

Systematic review, level III.

Accuracy assessment of measuring component position after total ankle arthroplasty using a conventional method

Background

This study was to assess the accuracy of measuring the tibial and talar components position and to investigate the outlier rate of each component and predisposing factors related to component malalignment after total ankle arthroplasty (TAA) using a conventional method.

Methods

One hundred fifty consecutive primary total ankle arthroplasty were performed using the three-component HINTEGRA prosthesis for ankle end-stage osteoarthritis. Radiographic analysis for the accuracy of component position in coronal and sagittal plane was conducted at postoperative 6 months. Additionally, the accuracy of component position was evaluated according to presence of preoperative deformity or joint incongruency.

Results

The mean postoperative coronal angles of the tibial and talar components (α and γ) were 91.9° and 91.3°. The mean postoperative sagittal angles of the tibial and talar components (β and δ angle) were 84.6° and 91.7°. In the coronal plane, 16 (10.7%) tibial components and 15 (10.0%) talar components showed outliers greater than 5°. In sagittal plane, 15 (10.0%) tibial components and 29 (19.3%) talar components showed outliers greater than 5°. There was no meaningful increase of the outlier rate regarding presence of preoperative deformity or joint incongruency.

Conclusions

In conventional method of TAA, the outlier rate of the tibial and talar components was about 10 to 20%, especially, the outlier rate of talar component in sagittal plane was up to 20%. Therefore, careful attention should be paid to implant the talar component in conventional TAA.

Survival of the Scandinavian total ankle replacement (STAR): results of ten to nineteen years follow-up

PURPOSE

The purpose of this study was to evaluate survival and clinical outcome of the Scandinavian total ankle replacement (STAR) prosthesis after a minimum of ten years up to a maximum of 19 years.

METHODS

Fifty STAR prostheses in 46 patients with end stage ankle osteoarthritis operated between 1996 and 2006 by the same surgeon (MH) were included. Minimal follow-up was ten years (median 14.6 years, 95% confidence interval [CI] 12.9-16.4). Clinical (Kofoed score) and radiological assessments were taken before the operation and at one, ten (+2), and 16 (±3) years after implantation. The primary endpoint was defined as exchange of the whole prosthesis or conversion to arthrodesis (def. 1), exchange of at least one metallic component (def. 2), or exchange of any component including the inlay (due to breakage or wear) (def. 3). Survival was estimated according to Kaplan-Meier. Further reoperations related to STAR were also recorded.

RESULTS

The ten year survival rate was (def. 1) 94% (CI 82-98%), (def. 2) 90% (CI, 77-96%), and (def. 3) 78% (CI 64-87%). The 19-year survival rate was (def. 1) 91% (CI 78-97%), (def. 2) 75% (CI 53-88%), and (def. 3) 55% (CI 34-71%). Considering any re-operations related to STAR, 52% (26/50) of prostheses were affected by re-operations. Mean pre-operative Kofoed score was 49, which improved to 84 after one year (n = 50), to 90 after ten years (n = 46), and to 89 after 16 years (n = 28).

CONCLUSIONS

The survival rate for def. 1 and 2 was high. However, re-operations occurred in 52% of all STAR prosthesis.

STUDY DESIGN

Retrospective cohort study, evidence Level 4.

Long-term Results of Scandinavian Total Ankle Replacement

BACKGROUND

The purpose of this study was to evaluate the long-term results of the Scandinavian Total Ankle Replacement (STAR) implant in a single center.

METHODS

Between 1997 and 2002, 34 consecutive ankles were replaced with the STAR ankle prosthesis and reviewed in 2016. Patients were followed both radiologically and clinically; clinical outcomes were measured with the Kofoed ankle score and subjective measurements. The median follow-up period was 159 months (13.3 years; range, 13-202 months).

RESULTS

The implant survival rate was 93.9% (95% confidence interval [CI], 92.2%-86.7%) at 5 years, 86.7% (95% CI, 69.3%-96.2%) at 10 years, and 63.6% (95% CI, 30.8%-89.0%) at 15 years. A total of 15 ankles (44%) had been revised: 2 by fusion, 3 by further replacement, 5 by insert exchange, and 5 by bone grafting for marked osteolysis. The improvements in the Kofoed ankle score and Kofoed ankle score for pain were statistically significant at every postoperative evaluation point compared to the preoperative values (all P < .0001), and subjective patient satisfaction was high.

CONCLUSION

Our results were satisfactory and in agreement with previously reported findings of STAR implants.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Pearls and Pitfalls for a Surgeon New to Ankle Replacements

The role of the surgeon learning curve in total ankle replacement (TAR) has produced contradictory results. It is important for a new surgeon to know what clinical and radiological parameters are considered reliable and ideal. It is clear that exposure to a high-volume center will increase the reliability of a new surgeon approaching TAR. Implant choice may be influenced by surgeon training, and the debate of mobile versus fix-bearing prosthesis is still open. Anterior versus lateral approach is still an open debate, with any hypothetical advantages given by the direct vision on the center of rotation to be proven.

The Regionalization of Total Ankle Arthroplasties and Ankle Fusions in New York State: A 10-Year Comparative Analysis

BACKGROUND

Total ankle arthroplasty (TAA) provides an alternative to ankle fusion (AF). The purpose of this study is to (1) determine the extent of TAA regionalization, as well as examine the growth of TAA performed at high-, medium-, and low-volume New York State institutions and (2) compare this regionalization and growth with AF.

METHODS

The New York Statewide Planning and Research Cooperative System (SPARCS) administrative data were used to identify 737 primary TAA and 7453 AF from 2005 to 2014. The volume of TAA and AF surgery in New York State was mapped according to patient and hospital 3-digit zip code.

RESULTS

The number of TAA per year grew 1500% (from 11 to 177) from 2005 to 2014, while there was a 35.6% reduction (from 895 to 576) in yearly AF procedures. TAA recipients were widely distributed throughout the state, while TAA procedures were regionalized to a few select metropolitan centers. AF procedures were performed more uniformly than TAA. The number of TAA has continued to increase at high- (15 to 91) and medium-volume (14 to 67) institutions where it has decreased at low-volume institutions (44 to 19).

CONCLUSION

The increased utilization of TAA is attributed to relatively few high-volume centers located in major metropolitan centers.

LEVELS OF EVIDENCE

Level IV: well-designed case-control or cohort studies.

Results at a minimum follow-up of 5 years of a ligaments-compatible total ankle replacement design

BACKGROUND

A new design of 3-part ankle replacement was developed to achieve compatibility with the natural ligaments by allowing certain fibers to remain isometric during passive motion.

METHODS

We evaluate 75 ankle prostheses implanted from July 2003 to December 2008, at a mean follow-up 6.5±1.1years (range 5-9 years). The mean age at surgery was 62±13years (range 29-82).

RESULTS

The mean AOFAS scores achieved at pre-op and at last follow-up were respectively 37±5 (23-45) and 78±8 (64-98). (p<0.001). Clinical range of motion of the ankle measured by goniometer pre op was 1°±2 of dorsiflexion and 12°±4° of plantarflexion; at last follow-up range of motion increased to 6°±5° in dorsiflexion (p<0.01) and 18°±7° in plantarflexion (p<0.05). Radiographs showed no loosening and little signs of radiolucency. Two revisions necessitated component removal, neither for implant loosening. The overall survival rate was 97.3%.

CONCLUSIONS

Function and Range-of-motion showed significant improvements. These results demonstrate that ligaments-compatible shaped talar and tibial components, with a fully conforming interposed meniscal bearing, can provide satisfactory survival rates and clinical outcomes in the middle term.

Ratio of Range of Motion of the Ankle and Surrounding Joints After Total Ankle Replacement: A Radiographic Cohort Study

BACKGROUND

This study attempted to identify where motion occurs after total ankle replacement, the difference in range-of-motion contributions between fixed-bearing and mobile-bearing total ankle replacements, and the contribution of abnormal peritalar motion. We hypothesized that sagittal plane radiographic assessment would demonstrate that actual ankle motion through the prosthesis is less than the total arc of ankle motion that may be observed clinically secondary to contributions from adjacent joints.

METHODS

Patients underwent routine standardized weight-bearing maximum dorsiflexion and plantar flexion sagittal radiographs. Sagittal plane ankle and foot measurements were performed on each dorsiflexion and plantar flexion radiograph to determine the total arc of ankle motion, actual ankle motion through the prosthesis, motion through the subtalar and talonavicular joints, and midfoot motion. Motion radiographs were routinely made at 1 year postoperatively and at the time of the most recent follow-up. A minimum follow-up of 2 years was required of all patients.

RESULTS

There were 197 patients who met the inclusion criteria (75 INBONE, 52 Salto Talaris, and 70 STAR prostheses). The mean time to the latest radiographs (and standard deviation) was 42.9 ± 18.8 months. The mean actual ankle motion through the prosthesis was 25.9° ± 12.2°, which was significantly less (p < 0.001) than the mean total motion arc of 37.6° ± 12.0°. The motion of the ankle accounted for 68% of total range of motion, and motion of the peritalar joints accounted for 32%. There was no significant difference (p > 0.05) among the 3 prostheses or when comparing fixed and mobile-bearing designs for both ranges of motion.

CONCLUSIONS

This study demonstrates that actual ankle motion after total ankle replacement is approximately 12° less than the total arc of motion that might be observed clinically because of increased midfoot and subtalar motion.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Long-term Functional and Radiographic Outcome of a Mobile Bearing Ankle Prosthesis

BACKGROUND

Total ankle arthroplasty is an accepted alternative to arthrodesis of the ankle. However, complication and failure rates remain high. Long-term results of the Scandinavian Total Ankle Replacement (STAR) are limited, with variable complication and failure rates observed. This prospective study presents the long-term survivorship and postoperative complications of the STAR prosthesis.

METHODS

Between May 1999 and June 2008, 134 primary total ankle arthroplasties were performed using the STAR prosthesis in 124 patients. The survivorship, postoperative complications, and reoperations were recorded, with a minimum follow-up period of 7.5 years. Clinical results were assessed using the Foot Function Index and the Kofoed score. The presence of component migration, cysts, and radiolucency surrounding the prosthesis components, heterotopic ossification, and progression of osteoarthritis in adjacent joints were determined.

RESULTS

The cumulative survival was 78% after the 10-year follow-up period. An ankle arthrodesis was performed in 20 ankles (14.9%) that failed. Fourteen polyethylene insert fractures occurred (10.4%). Other complications occurred in 29 ankles (21.6%), requiring secondary procedures in 21 ankles (15.7%). Nevertheless, the postoperative clinical results improved significantly. Osteolytic cysts were observed in 61 ankles (59.8%) and the surface area of these cysts increased during follow-up, without any association with the prosthesis alignment or clinical outcome. Heterotopic ossification at the medial malleolus was present in 58 cases (56.8%) and at the posterior tibia in 73 cases (71.6%), with no effect on clinical outcome. Osteoarthritis of the subtalar and talonavicular joint developed in 9 (8.8%) and 11 cases (10.8%), respectively.

CONCLUSION

The long-term clinical outcomes for the STAR were found to be satisfactory. Although these results are consistent with previous studies, the survival and complication rates are disappointing compared to knee and hip arthroplasty. Higher rates of successful outcomes following ankle arthroplasty are important, and these results highlight the need for further research to clarify the origin and significance of the reported complications.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Anterior Approach Total Ankle Arthroplasty: Superficial Peroneal Nerve Branches at Risk

In ankle arthroplasty, little attention has been given to intraoperative nerve injury and its postoperative sequelae. The aim of the present anatomic study was to determine the relationship of the superficial peroneal nerve to the standard anterior approach for total ankle arthroplasty. The superficial peroneal nerve was dissected in 10 below-the-knee cadaver specimens. The medial and intermediate dorsal cutaneous branches were identified. A needle was placed at the ankle joint. The following measurements were recorded: bifurcation into the medial and intermediate dorsal cutaneous branches, reference needle to the branches of the medial and intermediate superficial peroneal nerve, and the crossing branches of the medial dorsal cutaneous nerve. Two specimens (20%) had a medial dorsal cutaneous branch cross from medially to laterally. Eight specimens (80%) had a crossing branch of the medial dorsal cutaneous branch within 5 cm of the incision. No intermediate dorsal cutaneous branches were within the incision. The results from the present cadaver study suggest that during an anterior ankle approach, aberrant branches of the superficial peroneal nerve could require transection in 20% of patients at the joint level and ≤80% of patients with distal extension >35 mm from the ankle joint. The risk of injury to branches of the superficial peroneal nerve is substantial. The risk of nerve injury can be decreased with meticulous operative technique, smaller incisions, and the avoidance of aggressive retraction.

Inconsistency in the Reporting of Adverse Events in Total Ankle Arthroplasty: A Systematic Review of the Literature

BACKGROUND

Systems for classifying complications have been proposed for many surgical subspecialties. The goal of this systematic review was to analyze the number and frequency of different terms used to identify complications in total ankle arthroplasty. We hypothesized that this terminology would be highly variable, supporting a need for a standardized system of reporting.

METHODS

Studies that met predefined inclusion/exclusion criteria were analyzed to identify terminology used to describe adverse events. All terms were then tabulated and quantified with regard to diversity and frequency of use across all included studies. Terms were also grouped into 10 categories, and the number of reported occurrences of each adverse event was calculated. A reporting tool was then developed.

RESULTS

Of 572 unique terms used to describe adverse outcomes in 117 studies, 55.9% (320/572) were used in only a single study. The category that was most frequently reported was revision surgery, with 86% of papers reporting on this event using 115 different terms. Other categories included "additional non-revision surgeries" (74% of papers, 93 terms), "loosening/osteolysis" (63% of papers, 86 terms), "fractures" (60% of papers, 53 terms), "wound problems" (52% of papers, 27 terms), "infection" (52% of papers, 27 terms), "implant problems" (50% of papers, 57 terms), "soft tissue injuries" (31% of papers, 30 terms), "heterotopic ossification" (22% of papers, 17 terms), and "pain" (18% of papers, 11 terms).

CONCLUSION

The reporting of complications and adverse outcomes for total ankle arthroplasty was highly variable. This lack of consistency impedes the accurate reporting and interpretation of data required for the development of cohesive, evidence-based treatment guidelines for end-stage ankle arthritis. Standardized reporting tools are urgently needed. This study presents a prototype worksheet for the standardized assessment and reporting of adverse events.

LEVEL OF EVIDENCE

Level-III, decision analyses, systematic review of Level III studies and above.

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.

Effect of Obesity on Total Ankle Arthroplasty Outcomes

BACKGROUND

The purpose of this study was to evaluate the effect of obesity on intermediate- to long-term implant failure rates and survivorship after total ankle arthroplasty.

METHODS

A chart review was performed for all patients who underwent primary total ankle arthroplasty between 2004 and 2009 with a minimum 5-year follow-up. Patients were separated into a reference group with a body mass index less than 30 kg/m2 and an obese group with an index greater than or equal to 30 kg/m2. Minimum 5-year follow-up outcomes were available for 49 patients in the obese group and 48 patients in the nonobese group. Mean follow-up was 8.2 ± 2.0 years (range, 5.1-11.5 years) in the reference group and 7.7 ± 2.0 years (range, 5.0-11.9 years) in the obese group (P = .26).

RESULTS

Based on multivariable logistic regression, obese patients had a significantly greater probability of implant failure by final follow-up (adjusted odds ratio, 2.8 [95% CI, 1.04-7.53]; P = .04). Cox regression analysis of 5-year implant survivorship showed no significant difference between the 2 groups (adjusted hazard ratio, 1.89 [95% CI, 0.77-4.65]; P = .17). When compared with obese patients with inflammatory or posttraumatic arthritis, obese patients with osteoarthritis demonstrated a significantly decreased 5-year survivorship (adjusted hazard ratio, 3.73 [95% CI, 1.05-10.43]; P = .04).

CONCLUSION

This study demonstrated an increased long-term risk of implant failure among obese patients that was not seen in the intermediate term. Furthermore, obese patients with primary osteoarthritis were found to have a significantly decreased 5-year implant survivorship after ankle arthroplasty as compared with obese patients with inflammatory or posttraumatic arthritis and therefore should be counseled appropriately when deciding between arthroplasty and arthrodesis.

LEVEL OF EVIDENCE

Level III, retrospective comparative series.

Survival Analysis of the Single- and Double-Coated STAR Ankle up to 20 Years: Long-Term Follow-up of 324 Cases From the Swedish Ankle Registry

BACKGROUND

The Scandinavian Total Ankle Replacement (STAR) has been used widely in Europe and more recently in the United States. We studied the results of the single-coated and the double-coated STAR with long-term follow-up.

METHODS

All STARs (n = 324) used in Sweden (first implanted in 1993) were included. Prosthetic survival was estimated according to Kaplan-Meier.

RESULTS

The 14-year survival of the single-coated STAR was 0.47 (95% confidence interval [CI], 0.38-0.66), and the 12-year survival of the double-coated STAR was 0.64 (95% CI, 0.57-0.71). Women younger than 60 years with osteoarthritis had a statistically significantly higher risk of revision than men and than patients with other diagnoses.

CONCLUSION

The long-term results of the STAR prosthesis are not encouraging. The results seem to deteriorate by time.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Articular congruency of the Salto Talaris total ankle prosthesis

BACKGROUND

The Salto-Talaris polyethylene articulating surface was designed to allow, but limit accessory motion. This investigation examines surface characteristics between the polyethylene bearing and anatomic talar component in various positions of function.

METHODS

A Salto Talaris talar prosthesis and matching polyethylene bearing were scanned to create digital solid body models and manipulated to assess surface contact during simulated gait. With computer micromanipulation of the component positions, the surface intersections were recorded for 15 different alignments.

RESULTS

The Salto Talaris has limited contact congruity with four points of contact in dorsiflexion, neutral, and plantarflexion. Lateral and medial translations showed only 2-point contact. The radii of curvatures between the talar component and polyethylene surfaces do not match. There was no sulcus contact yet component separation distance was small, suggesting increased loads.

CONCLUSION

Surface incongruency was measured based on computer model analysis which raises a concern of increased contact pressures.

Use of Negative Pressure Wound Therapy on Closed Surgical Incision After Total Ankle Arthroplasty

BACKGROUND

Wound healing problems of the anterior ankle incision are among the most common complications after total ankle arthroplasty, possibly resulting in exposure of the prostheses and infection. The aim of this study was to investigate the role of negative pressure wound therapy (NPWT) in decreasing the rate of wound healing problems after total ankle arthroplasty.

METHODS

This is a retrospective cohort study including consecutive patients who underwent total ankle arthroplasty by a single surgeon at a single institution between 2009 and 2013. The incisional negative pressure dressing was applied to all patients who underwent total ankle arthroplasty between 2012 and 2013 with a continuous application of -80 mm Hg negative pressure for 6 days postoperatively. The control group consisted of patients who underwent total ankle arthroplasty between 2009 and 2012 with a conventional nonadherent gauze dressing. Seventy-four patients were involved in this study: 37 in the control group and 37 in the incisional NPWT group.

RESULTS

All patients tolerated the incisional NPWT to completion without any dressing failures or skin problems. Both groups showed similar distributions in demographics and perioperative risk factors for wound healing. There were 9 (24%) wound healing problems in the control group and 1 (3%) in the incisional NPWT group. Incisional NPWT was found to reduce wound healing problems with an odds ratio of 0.10 (95% CI, 0.01-0.50; P = .004).

CONCLUSIONS

Our study demonstrated that there was a decreased incidence of wound healing problems following total ankle arthroplasty with incisional NPWT dressings. This is the first study evaluating the efficacy of incisional NPWT as an adjunct treatment for wound healing after total ankle arthroplasty.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Intermediate to Long-Term Outcomes of Total Ankle Replacement with the Scandinavian Total Ankle Replacement (STAR)

BACKGROUND

The Scandinavian Total Ankle Replacement (STAR) prosthesis has been in clinical use since 1981, with investigational use in the U.S. since 1998. Few studies of the North American version of the STAR are available. This prospective cohort study analyzed intermediate to long-term outcomes of total ankle arthroplasty with use of the STAR prosthesis at two Canadian centers.

METHODS

Consecutive patients who received the STAR prosthesis between 2001 and 2005 were enrolled at two large, urban teaching hospitals. Patients were annually evaluated clinically, and the Ankle Osteoarthritis Scale (AOS) and the Short Form (SF)-36 were administered.

RESULTS

One hundred and eleven ankles underwent arthroplasty with the STAR prosthesis. One-half of the patients were male; the mean age was 61.9 ± 11.7 years. Sixty-eight of the ankles underwent a total of 121 additional procedures during ankle arthroplasty, including gastrocnemius release, subtalar arthrodesis, triple arthrodesis, tendoachilles lengthening, and removal of hardware. The mean duration of follow-up for all living patients without revision (seventy-three ankles) was 9.0 ± 1.0 years. Thirteen (12%) of the ankles required metal component revision at a mean of 4.3 ± 3.0 years (range, 0.6 to 10.2 years). Twenty (18%) of the prostheses underwent polyethylene bearing exchange, mostly due to fracture, at a mean of 5.2 ± 2.1 years (range, 1.5 to 9.3 years). Most (97%) of the revisions and exchanges occurred in patients with a diagnosis of primary, secondary, or posttraumatic osteoarthritis (p = 0.0003). The mean change from baseline to final follow-up was -36.5 ± 23.3 points for AOS pain, -38.6 ± 26.8 points for AOS disability, and 9.6 ± 10.3 points for the SF-36 physical component summary score. The SF-36 mental component summary score was unchanged.

CONCLUSIONS

Intermediate patient-reported outcomes were good after ankle arthroplasty with the STAR prosthesis performed by experienced surgeons, and long-term outcomes demonstrated a 12% rate of metal component revision and 18% rate of polyethylene bearing failure. The revision rate was substantially higher among the first twenty ankles than among subsequent ankles, but the early ankles had nearly two years' longer follow-up than subsequent ankles. Additional study to elucidate possible reasons for polyethylene bearing failure is warranted.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Poor accuracy of plain radiographic measurements of prosthetic migration and alignment in total ankle replacement

BACKGROUND

The rotational position of the leg substantially influences measurements in ankle radiographs after total ankle replacement (TAR). The aim of our study was to further specify the influence of different projections on radiographic parameters used to assess component position after TAR.

METHODS

The effect of varying degrees of internal rotation, flexion, and ab-/adduction on reference lines in anteroposterior and lateral ankle radiographs was investigated in a cadaveric TAR model. Observed variations were then compared with those found in 34 consecutive patients that received a HINTEGRA total ankle prosthesis in our department.

RESULTS

A change of rotation of 20° resulted in a variation of measured reference lines of more than 1.3 cm in anteroposterior radiographs and more than 1 cm in lateral radiographs in our experimental setting. Even higher intraindividual changes of up to 1.4 cm were observed in our in vivo series.

CONCLUSIONS

The findings suggest that rotational position of the leg highly influences measurements in ankle radiographs after TAR. It further raises the question, if previously described radiographic parameters do provide accurate information for the outcome after TAR in clinical routine as suggested in literature.

Posterior Tibial Artery Perforator-Based Fascial Flap for Skin Necrosis and Exposed Extensor Tendon After Revision Total Ankle Replacement

CASE

Delayed wound-healing of anterior ankle incisions can be problematic for patients who have undergone total ankle replacement. We describe the case of a patient in whom a posterior tibial artery perforator-based fascial flap was effectively used to cover skin necrosis and to repair the extensor retinaculum in a wound following revision total ankle replacement.

CONCLUSION

When a tendon is exposed in the ankle, a skin flap is generally required. The creation of a perforator-based fascial flap is a useful technique for covering a wound with an exposed tendon and is an alternative to a musculocutaneous flap.

Inferior results of salvage arthrodesis after failed ankle replacement compared to primary arthrodesis

BACKGROUND

Up to now, there has been no evidence that salvage arthrodesis would perform inferior when compared with primary ankle arthrodesis. The purpose of this study was to compare their clinical and radiographic results.

METHODS

A retrospective analysis was performed using 2 validated scores and assessment of radiographic union by comparing 23 patients who underwent salvage ankle arthrodesis (group SA = salvage arthrodesis) after failed total ankle replacement with 23 matched patients who received primary ankle arthrodesis (group PA = primary arthrodesis). The mean follow-up period was 38 (range 16-92) months in group SA and 56 (23-94) months in group PA.

RESULTS

Complete union was achieved in 17 patients (74%) after a mean time of 50 (13- 114) weeks in group SA and in 16 patients (70%) after a mean time of 23 (10-115) weeks in group PA. The SF-36 score averaged 48 points (7-80) in SA and 66 points (14-94; P = .006) in group PA. In group SA the mean FFI was 57% (22-82) for pain and 71% (44-98) for function. In group PA significantly better results for pain with 34% (0-88; P = .002) and function with 48% (1-92; P = .002) were found.

CONCLUSION

Salvage arthrodesis led to impaired life quality and reduced function combined with significantly higher pain when compared with primary ankle arthrodesis. These findings can be used to counsel our patients preoperatively.

LEVEL OF EVIDENCE

Level III, retrospective case series.

Investigating the relationship between ankle arthrodesis and adjacent-joint arthritis in the hindfoot: a systematic review

BACKGROUND

Ankle arthrodesis traditionally has been regarded as the treatment of choice for many patients with end-stage ankle arthritis. However, a major reported risk of ankle arthrodesis is adjacent-joint degeneration. There are conflicting views in the literature as to the causative link between ankle arthrodesis and progression to adjacent-joint arthritis. Recent studies have challenged the causative link between arthrodesis and adjacent-joint arthritis, purporting that preexisting adjacent-joint arthritis is present in many patients. The aim of the present study was to systematically review the available literature to determine if there is sufficient evidence to support either hypothesis.

METHODS

A literature search of the EMBASE and PubMed/MEDLINE databases (1974 to present) was performed. A total of twenty-four studies were included for review. The studies were reviewed, and the relevant information was extracted, including research methodology, postoperative outcomes in the adjacent joints of the foot, and whether pre-arthrodesis radiographs and medical records were available for analysis.

RESULTS

The twenty-four manuscripts included eighteen clinical studies, five biomechanical studies, and one gait-analysis study. The majority of biomechanical studies showed altered biomechanics in the fused ankle; however, there was no clear consensus as to whether these findings were causes of adjacent-joint arthritis. In studies assessing clinical outcomes, the reported prevalence of subtalar joint arthritis ranged from 24% to 100% and the prevalence of talonavicular and calcaneocuboid arthritis ranged from 18% to 77%. Correlation between imaging findings of arthritis in adjacent joints and patient symptoms was not established in a number of the clinical studies reviewed.

CONCLUSIONS

There is no true consensus in the literature as to the effects of ankle arthrodesis on biomechanics or whether ankle arthrodesis leads to adjacent-joint arthritis. Similarly, a correlation between postoperative imaging findings and clinical presentation in this cohort of patients has not been conclusively demonstrated.