Long-term results of total ankle replacement

Anterior Ankle Incision Wound Complications Between Total Ankle Replacement and Ankle Arthrodesis: A Matched Cohort Study

The anterior incision is commonly used for total ankle replacement (TAR) and ankle arthrodesis. Historically, the anterior incision has demonstrated a high incidence of complications. The purpose of this study was to evaluate anterior incisional healing and soft tissue complications between TAR and ankle arthrodesis with anterior plate fixation.This was an IRB-approved retrospective review of wound healing and other complications among 304 patients who underwent primary TAR (191 patients) or ankle arthrodesis (113 patients) via the anterior approach over a 4-year period. The operative approach, intraoperative soft tissue handling, and postoperative protocol for the first 30 days were the same between groups. The mean follow-up was 11.8 months. To diminish the effect of selection bias, a subgroup analysis was performed comparing 91 TAR patients matched to an equal number of demographically similar ankle arthrodesis patients. Overall, 19.7% of patients experienced delayed wound healing greater than 30 days. Although the TAR and arthrodesis subgroups had dissimilar demographics, there was no difference in outcomes. Between matched pairs, no statistically significant differences were observed; however, trends were identified with matched cohort groups when compared to the overall patient series. These trends toward statistically significant differences in delayed wound healing and incidence of wound care in the matched cohort groups warrants further investigation in larger series or multicenter study. Further work is needed to identify the modifiable risk factors associated with the anterior ankle incision.

Outcomes Following Total Ankle Arthroplasty: A Review of the Registry Data and Current Literature

End-stage ankle arthritis has a significant effect on function and quality of life. Total ankle arthroplasty continues to emerge as a safe and effective treatment of ankle arthritis. Ankle arthroplasty preserves motion at the ankle joint, while still achieving the primary goal of pain relief. With encouraging outcomes and improved implant longevity, there has been significant improvement on the results of first-generation implants. Further high-quality studies are required to clarify outcomes post ankle arthroplasty. This article reviews the latest data from national registries and the wider literature to evaluate the current status with outcomes of modern total ankle replacements.

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.

Complex Total Ankle Arthroplasty

Total ankle arthroplasty is a viable surgical technique for the treatment of end-stage degenerative joint disease. With continued advancement in prosthetic design, refined surgical techniques, and improved outcomes, the indications for total ankle replacement have expanded to include cases of increasing complexity. With meticulous preoperative planning and exacting execution, many frontal plane deformities and cases of avascular necrosis can now be successfully addressed at the time of prosthesis implantation or in a staged procedure.

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.

Functional and clinical outcomes of total ankle arthroplasty in elderly compared to younger patients

BACKGROUND

Total ankle arthroplasty (TAA) is becoming an increasingly utilized procedure for the management of end-stage ankle arthritis. Elderly patients are the fastest growing segment of the population in the western world, creating a unique challenge to the health economics of our era. Determining if elderly patients with end-stage ankle arthritis demonstrate the same improvements in clinical outcomes and functional measures of gait following TAA would be valuable. This can aid to evaluate the utilization of TAA in this enlarging cohort of our population.

METHODS

Consecutive series of twenty-one patients over the age of 70, who underwent TAA for end-stage ankle arthritis, was prospectively compared to a series of twenty-one patients aged 50-60, who underwent the same procedure by single surgeon during same time period. Clinical outcomes were measured with outcome scores including VAS pain score, AOFAS Ankle and Hindfoot Score, and the SF-36. Three-dimensional gait analysis was performed preoperatively and at a minimum of one year postoperatively, to measure temporal-spatial, kinematic, and kinetic parameters of gait. Mixed model multivariate statistical analysis was used to evaluate and compare the independent contributions to outcomes of the surgical intervention over time; of patient age; and of time-plus-age interaction, as these influenced both the clinical outcomes and the functional gait outcomes.

RESULTS

Statistically significant improvements in VAS pain scores, AOFAS ankle/hindfoot scores, and SF-36 scores were demonstrated in both age groups. Following surgery, there were improvements in all parameters of gait, including temporal-spatial parameters as step length and walking velocity; kinematic parameters, including, increase in total range of motion to a total of 17-19°; and kinetic parameters, including increase in ankle power and moment. The improvements both in clinical and gait outcomes were equivalent in the two age groups.

CONCLUSIONS

In this comparative study, it is shown that both elderly patients over the age of 70 and younger patients aged 50-60 demonstrated equivalent improvements clinical and gait outcomes following ankle arthroplasty. This may be important data both for clinical decision-making and the health economics for our ageing population.

Evaluating Component Migration: Comparing Two Generations of the INBONE(®) Total Ankle Replacement

Although total ankle replacement (TAR) designs have radically evolved, the compressive forces at the ankle can cause aseptic loosening, talar subsidence, and implant failure. The purpose of the present report was to compare the implant migration associated with the INBONE(®) I, a TAR system with a stemmed talar component, and the newer generation INBONE(®) II, a TAR system without a stemmed talar component (Wright Medical Technology, Inc., Arlington, TN). Because core decompression could weaken the integrity of the talus, we hypothesized that the stemmed component would result in greater implant migration. A total of 35 consecutive patients (age 58.2 ± 12.1 years; 23 men) were included. Of these 35 patients, 20 (57.1%) had been treated with the INBONE(®) I and 15 (42.9%) with the INBONE(®) II. To assess implant migration, using anteroposterior radiographs, the distance from the apex of the tibial component to the most distal aspect of the talar stem or to the mid-saddle of the nonstemmed component was measured. The measurements were recorded from the immediate postoperative radiographs and the 12-month postoperative radiographs. Implant migration was quantified as the difference between the 12-month and the immediate postoperative measurements. Despite our hypothesis, no significant difference was found in implant migration between the INBONE(®) I (0.7 ± 1.2 mm) and INBONE(®) II (0.6 ± 1.3 mm, p = .981). However, previously published data have suggested that implant migration can continue for ≥2 years after surgery. Therefore, additional investigations with larger sample sizes and longer follow-up periods are needed to draw definitive conclusions.

Preoperative and Postoperative Range of Motion: A Retrospective Comparison of Two Total Ankle Replacement Systems

The purpose of the present report was to compare the range of motion between a total ankle replacement requiring arched bony resection and a total ankle replacement requiring a flat cut for implantation. We hypothesized that the arched contour would more closely mimic the patient's pre-existing anatomy and increase the range of motion. Pain was evaluated as a secondary outcome. Twenty-eight patients (age 55.95 ± 15.29 years) were included. Of the 28 patients, 14 were treated with an arch cut and 14 with a flat cut. Although no significant difference was found in dorsiflexion between the 2 implant groups (p = .38), preoperative dorsiflexion, body mass index, implant type, and preoperative plantarflexion emerged as significant predictors of postoperative plantarflexion (p = .04). This finding indicates that postoperative plantarflexion was significantly greater in patients treated with an arch cut (30.43° ± 10.01°) than a flat cut (21.79° ± 15.70°, p = .02), when controlling for the other explanatory variables. A statistically significant improvement in pain was observed after total ankle replacement (p < .001). The mean change in pain was similar for the 2 implant groups when statistically controlling for the follow-up duration (p = .09). The findings from the present report suggest that plantarflexion significantly improves after total ankle replacement requiring an arched cut for implantation. Future studies should be designed to control for potentially confounding variables and assess the differences in range of motion after total ankle replacement.

Influence of crosslinking on the wear performance of polyethylene within total ankle arthroplasty

BACKGROUND

Wear debris of polyethylene within joint replacement systems can result in clinical complications including osteolysis and component loosening. Highly crosslinked polyethylene (HXPE) was introduced to improve these outcomes, and has been shown to result in improved wear performance in several joint replacement systems. However, bearing couples within total ankle replacement (TAR) systems have historically used conventional polyethylene (CPE) articulating on metal. The extent to which HXPE would result in a reduction of polyethylene wear compared to CPE in the ankle has not been studied. The hypothesis motivating this study was that use of HXPE within TAR will result in significantly lower wear rate than CPE.

METHODS

HXPE and CPE inserts within a semiconstrained, bicondylar TAR system were manufactured for this study. Samples were subjected to 5.0 million cycles of wear on an in vitro wear simulator. Testing was performed within a physiological environment, using kinematic and kinetic loading profiles characteristic of walking gait. Samples were weighed at regular intervals to determine gravimetric mass loss, and the morphology of wear particles was analyzed.

RESULTS

The wear rates for CPE and HXPE samples were 7.4 ± 1.3 and 1.9 ± 0.3 mg/Mc (mean ± SD), respectively. HXPE samples exhibited a significant (P < .01) wear rate reduction of 74% when compared with the CPE. Debris morphology trends between HXPE and CPE were consistent with what has been observed in other joint systems.

CONCLUSION

Use of HXPE significantly reduces wear of TAR as compared to CPE, based on in vitro wear testing.

CLINICAL RELEVANCE

Highly crosslinked polyethylene may reduce clinical complications of total ankle replacement that are linked to polyethylene wear.

Modular stem fixed-bearing total ankle replacement: prospective results of 23 consecutive cases with 3-year follow-up

In the present report, the 3-year outcomes of 23 consecutive patients treated with a modular stem fixed-bearing total ankle replacement are described. Pain, functional impairment, and disability were assessed annually using a visual analog scale. Complications and additional procedures also were recorded. Compared with preoperative pain (8.4 ± 1.4), functional impairment (8.7 ± 2.3), and disability (3.0 ± 2.5), there were statistically significant postoperative improvements at 1 year (pain, 2.6 ± 1.6; functional impairment, 3.1 ± 2.1; disability, 0.9 ± 1.2), 2 years (pain, 1.5 ± 1.3; functional impairment, 1.9 ± 1.4; disability, 0.6 ± 1.4), and 3 years (pain, 1.3 ± 1.3; functional impairment, 1.9 ± 1.9; disability, 0.4 ± 0.9; p ≤ .001). Pain, function, and disability significantly improved postoperatively from 1 to 2 years (p ≤ .008) and from 1 to 3 years (p ≤ .008). The reductions in pain, functional impairment, and disability were maintained from 2 to 3 years (p ≥ .08). Nine complications (39.1%) were encountered: 1 deep infection, 2 pulmonary embolisms, 3 wounds, 1 ectopic bone formation, 1 stiff joint, and 1 talar subsidence. In the 3-year follow-up period, 3 patients (13.0%) required additional procedures after the immediate postoperative phase. Our results have demonstrated that modular stem fixed-bearing prostheses can be implanted in a predictable and consistent fashion with resultant improvements in pain, function, and disability. Future studies evaluating the clinical outcomes after modular stem fixed-bearing total ankle replacement are warranted.

Trends in the use of total ankle replacement and ankle arthrodesis in the United States Medicare population

BACKGROUND

Total ankle replacement (TAR) has gained acceptance as an alternative to traditional ankle arthrodesis (AA) for end-stage ankle arthritis. Little is known about long-term trends in volume, utilization, and patient characteristics. The objective of this study was to use longitudinal data to examine temporal trends in TAR and AA.

METHODS

We identified all United States fee-for-service Medicare beneficiaries who underwent TAR and AA between 1991 and 2010 (n = 5871 and 29 532, respectively). We examined changes in patient demographics and comorbidity, nationwide and hospital volume, per capita utilization, and length of stay (LOS).

RESULTS

Between 1991 and 2010, both TAR and AA patients had modest shifts in characteristics, with higher rates of diabetes and obesity. Overall, TAR Medicare volume increased by more than 1000% from 72 procedures in 1991 to 888 in 2010, while per-capita standardized utilization increased 670.8% (P < .001). AA volume increased 35.8% from 1167 procedures in 1991 to 1585 in 2010, while per-capita standardized utilization declined 15.6% (P < .001). The percentage of all US hospitals performing TAR increased nearly 4-fold from 3.1% in 1991 to 12.6% in 2010, while the proportion performing AA remained relatively unchanged. LOS decreased dramatically from 8.7 days in 1991 to 2.3 days in 2010 in TAR and from 5.5 days to 3.2 days in AA (P < .001).

CONCLUSION

Between 1991 and 2010, Medicare beneficiaries undergoing either TAR or AA became more medically complex. Both volume and per-capita utilization of TAR increased dramatically but remained nearly constant for AA. At the same time, mean hospital volume for both procedures remained low. Further research should be directed toward determining design, surgeon, and hospital variables that relate to optimal outcomes following TAR, which has become increasingly used for the treatment of ankle arthritis.

LEVEL OF EVIDENCE

Level III, comparative series.

Biologic augmentation of foot and ankle arthrodeses with an allogeneic cancellous sponge

This case series was conducted to assess the safety and efficacy of using an allogeneic cancellous bone sponge for augmentation of foot and ankle arthrodeses. Twenty-five patients were prospectively enrolled in the study prior to undergoing fusion and were then followed for 12 months postoperatively. There were 45 joints: 7 ankles, 12 subtalars, 12 talonaviculars, 6 calcaneocuboids, 1 naviculocuneiform, 6 first tarsometatarsals, and 1 second tarsometatarsal. Patient-reported outcomes of pain (visual analog scale) and function (American Orthopaedic Foot and Ankle Society score) were obtained preoperatively and postoperatively at 6 and 12 months. No complications were noted intraoperatively or during the follow-up period. Three months postoperatively, radiographic osseous union was noted in 52% (13/25) of patients, which further increased to 96% (24/25) of patients at 6 and 12 months. There was no statistically significant difference in union time between joints [H(6)=11.5; P=.08]. Statistically significant improvements in pain (P≤.002) and function (P<.001) were observed across assessments. This study demonstrated that the cancellous bone sponge appears to be a safe and efficacious product. Randomized controlled trials are warranted to determine if the allogeneic cancellous sponge improves fusion rate, pain, and function.

Hindfoot motion following STAR total ankle arthroplasty: a multisegment foot model gait study

BACKGROUND

One of the rationales for total ankle arthroplasty (TAA) is that it may retard the changes of hypermobility and accelerated arthritis in the hindfoot after ankle arthrodesis. Until recently, it has not been possible to quantify or even objectively demonstrate biomechanical findings to substantiate the theory that postsurgical biomechanical changes in the ankle produce changes in the kinematics of the hindfoot. Standard gait analysis has treated the foot as a single biomechanical unit. This study was undertaken to describe the hindfoot motion following Scandinavian Total Ankle Replacement (STAR) TAA by using multisegment foot model gait analysis.

METHODS

Forty-six patients with a mean age of 66 years underwent a 3D gait analysis following TAR. Mean interval between surgery and gait analysis was 4.9 years (range 2 to 9). The contralateral limb was used as control for each patient. Temporospatial variables and kinematic parameters were studied.

RESULTS

Temporospatial results showed statistically significant differences. Stance time on the affected side was 61.1% ± 2.2% of the gait cycle compared to 63.2% ± 2.1% for the unaffected side. Step length was 55.6 cm ± 10 on the affected side compared to 53.9 cm ± 10 for the unaffected side. Kinematics results were statistically significant: Ankle range of motion (ROM) on the arthroplasty side was 16.8 ± 4.5 degrees compared to 23.6 ± 5.0 on the unaffected side. Sagittal plane ROM was 12.7 ± 4.2 degrees on the arthroplasty side and 17.3 ± 3.5 degrees on the unaffected side. Coronal plane ROM was 4.7 ± 2.4 degrees on the arthroplasty side and 7.5 ± 2.4 degrees on the unaffected side. Transverse plane ROM on the arthroplasty side was 4.1 ± 1.5 degrees and 4.9 ± 1.6 on the unaffected side.

CONCLUSION

This study showed that, in addition to previously documented diminution in sagittal plane motion and gait velocity, some of the residual abnormalities of gait following TAR were comprised of differences in hindfoot function. These results relate to the growing recognition of the importance of understanding hindfoot mechanics apart from those of the tibiotalar joint.

LEVEL OF EVIDENCE

Level III, comparative case series.

Comparison of gait after total ankle arthroplasty and ankle arthrodesis

BACKGROUND

Prior studies reported improved gait after total ankle arthroplasty and better parameters of gait than those reported in earlier studies of patients after ankle arthrodesis. However, there are very limited data prospectively evaluating the effects on gait after ankle arthroplasty compared with ankle arthrodesis. Controversy remains regarding the relative advantages and disadvantages of these 2 treatments and especially the differences in function between them.

METHODS

We performed a prospective study involving 28 patients with posttraumatic and primary ankle osteoarthritis and a control group of 14 normal volunteers. We compared gait in 14 patients who had undergone ankle arthrodesis with the gait of 14 patients who had ankle arthroplasty preoperatively and at 1 year postoperatively. Three-dimensional gait analysis was performed with a 12-camera digital-motion capture system. Temporospatial measurements included stride length and cadence. The kinematic parameters that were measured included the sagittal plane range of motion of the ankle and the coronal plane range of motion of the ankle. Double force plates were used to collect kinetic parameters such as ankle coronal and plantar flexion-dorsiflexion moments and sagittal plane ankle power. Center of pressure (CoP) and its progression in gait cycle were calculated.

RESULTS

Baseline parameters showed comparability among the treatment and control groups. Temporospatial analysis, using time as the main effect, showed that compared with ankle arthrodesis, patients with total ankle arthroplasty had higher walking velocity attributable to both increases in stride length and cadence as well as more normalized first and second rockers of the gait cycle. Kinematic analysis, using time and intervention as the main effects, showed that patients who had ankle arthroplasty had better sagittal dorsiflexion (P = .001), whereas those undergoing ankle arthrodesis had better coronal plane eversion (P = .01). Neither ankle arthrodesis nor arthroplasty altered the CoP progression during stance phase. Total ankle arthroplasty produced a more symmetrical vertical ground reaction force curve, which was closer to that of the controls than was the curve of the ankle arthrodesis group.

CONCLUSIONS

Patients in both the arthrodesis and arthroplasty groups had significant improvements in various parameters of gait when compared with their own preoperative function. Neither group functioned as well as the normal control subjects. Neither group was superior in every parameter of gait at 1 year postoperatively. However, the data suggest that the major parameters of gait after ankle arthrodesis in deformed ankle arthritis are comparable to gait function after total ankle arthroplasty in nondeformed ankle arthritis.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Comparison of the HINTEGRA and Mobility total ankle replacements

In a retrospective study we compared 32 HINTEGRA total ankle replacements (TARs) and 35 Mobility TARs performed between July 2005 and May 2010, with a minimum follow-up of two years. The mean follow-up for the HINTEGRA group was 53 months (24 to 76) and for the Mobility group was 34 months (24 to 45). All procedures were performed by a single surgeon.

There was no significant difference between the two groups with regard to the mean AOFAS score, visual analogue score for pain or range of movement of the ankle at the latest follow-up. Most radiological measurements did not differ significantly between the two groups. However, the most common grade of heterotopic ossification (HO) was grade 3 in the HINTEGRA group (10 of 13 TARs, 76.9%) and grade 2 in the Mobility group (four of seven TARs, 57.1%) (p = 0.025). Although HO was more frequent in the HINTEGRA group (40.6%) than in the Mobility group (20.0%), this was not statistically significant (p = 0.065).The difference in peri-operative complications between the two groups was not significant, but intra-operative medial malleolar fractures occurred in four (11.4%) in the Mobility group; four (12.5%) in the HINTEGRA group and one TAR (2.9%) in the Mobility group failed (p = 0.185).

Cite this article: Bone Joint J 2013;95-B:1075–82.

Failure modes of current total ankle replacement systems

Methodology for evaluation of total ankle replacements is described. Fusion and its problems are discussed as are those of total ankle joint replacement. Fusion is an imperfect solution because it reduces ankle functionality and has significant complications. Early fixed-bearing total ankles were long-term failures and abandoned. Currently available fixed-bearing ankles have proved inferior to fusion or are equivalent to earlier devices. Only mobile-bearing devices have been shown reasonably safe and effective. One such device, the STAR, has been approved by the Food and Drug Administration after a rigorous controlled clinical trial and is available for use in the United States.

Management of specific complications related to total ankle arthroplasty

Total ankle arthroplasty (TAA) has evolved over time and modern 3-component implants offer good and reliable clinical results. Despite recent improvements, TAA is still associated with a relatively high incidence of complications. Surgeon experience seems to play the most important role. This review highlights the most common intraoperative and postoperative complications, such as malleolar fracture, impingement, cyst formation, malalignment, and loosening, and offers a differentiated concept for their management.

The mobility total ankle replacement: techniques and pitfalls

The Mobility total ankle replacement (DePuy, Leeds, United Kingdom) is an uncemented, 3-component, mobile-bearing design. This article highlights the design rationale and explains the surgical technique with the Mobility implant, as well as offering technical tips and pitfalls gained through personal experiences and literature review. The tibial component has a flat articular surface and a conical intramedullary stem on the tibial side.

Total ankle replacement: a historical perspective

In the early 1970s, total ankle replacement was criticized because of poor outcomes with initial implant designs. Modifications were made that lead to the development of several generations of implants. The early shortcomings gave researchers and surgeons the impetus to improve implant designs and surgical technique. Total ankle replacement has become more widely accepted in recent years because of improved design and survivorship rates for the implants, as well as improved patient satisfaction scores. Indications for total ankle replacement have broadened. To continue these successes, it is important for surgeons to select appropriate patients for this procedure.

Tri-component, mobile bearing, total ankle replacement: mid-term functional outcome and survival

Tri-component, mobile bearing, uncemented, total ankle replacements were introduced after the high failure rates of cemented, highly constrained, first-generation, total ankle replacement implants. A total of 30 primary total ankle replacements in 29 patients (20 males and 9 females) were followed up in the present retrospective study for up to 13 (mean 5.1 ± 4) years. The postoperative functional and radiographic outcomes were measured. Failure was defined as revision of either of the components for any reason or conversion of the total ankle replacement to arthrodesis because of debilitating pain that did not resolve after surgery. Of the 29 patients, 2 underwent revision and 1 underwent arthrodesis. All 3 patients had the malpositioned talar implant revised. The mean American Orthopaedic Foot and Ankle Society score was 81 at 1 year postoperatively. Revision of the tibial or talar component for any reason or conversion of the ankle replacement to arthrodesis was considered failure for the survival analysis. Kaplan-Meier analysis showed a 5-year survival rate of 87.6%. The last failure occurred 23.3 months after surgery.

High revision and reoperation rates using the Agility™ Total Ankle System

BACKGROUND

Total ankle arthroplasty (TAA) is an evolving treatment for end-stage ankle arthritis, however, there is controversy regarding its longevity.

QUESTIONS/PURPOSES

We determined survival of the Agility™ TAA, the overall reoperation rate, and function in patients who retained their implant.

METHODS

We retrospectively reviewed 64 patients who had 65 TAAs between June 1999 and May 2001. Information was gathered through chart reviews, mailed-in questionnaires, and telephone interviews. Nine patients had died; data were available for 41 of the remaining 55 patients. Survival was based on revision as an end point. The minimum followup was 0.5 years (median, 8 years; range, 0.5-11 years).

RESULTS

Sixteen of the 41 patients (39%) needed revisions. The average time to revision surgery was 4 years with six of the revisions (38%) occurring within 1 year of the TAA. Of the 25 patients who retained their implants, 12 required secondary surgery for an overall reoperation rate of 28 of 41 (68%) at an average of 8 years followup. The average VAS pain score was 4, the average Foot and Ankle Ability Measure (FAAM) sports subscale score was 33, and the average FAAM activities of daily living subscale score was 57.

CONCLUSION

TAA had high revision and reoperation rates. Patients who retained their implant had only moderate pain relief and function. TAA must be approached with caution. More research is needed to elucidate the role of contemporary TAA.

Outcome of ankle arthrodesis in posttraumatic arthritis

BACKGROUND

Ankle arthrodesis is still a gold standard salvage procedure for the management of ankle arthritis. There are several functional and mechanical benefits of ankle arthrodesis, which make it a viable surgical procedure in the management of ankle arthritis. The functional outcomes following ankle arthrodesis are not very well known. The purpose of this study was to perform a clinical and radiographic evaluation of ankle arthrodesis in posttraumatic arthritis performed using Charnley's compression device.

MATERIALS AND METHODS

Between January 2006 and December 2009 a functional assessment of 15 patients (10 males and 5 females) who had undergone ankle arthrodesis for posttraumatic arthritis and/or avascular necrosis (AVN) talus (n=6), malunited bimalleolar fracture (n=4), distal tibial plafond fractures (n=3), medial malleoli nonunion (n=2). All the patients were assessed clinically and radiologically after an average followup of 2 years 8 months (range 1-5.7 years).

RESULTS

All patients had sound ankylosis and no complications related to the surgery. Scoring the patients with the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale, we found that 11 of the 15 had excellent results, two had good, and two showed fair results. They were all returned to their preinjury activities.

CONCLUSION

We conclude that, the ankle arthrodesis can still be considered as a standard procedure in ankle arthritis. On the basis of these results, patients should be counseled that an ankle fusion will help to relieve pain and to improve overall function. Still, one should keep in mind that it is a salvage procedure that will cause persistent alterations in gait with a potential for deterioration due to the development of subtalar arthritis.

Total ankle replacement with use of a new three-component implant

BACKGROUND

Total ankle arthroplasty has evolved over the past decade, and newer three-component implants have demonstrated favorable clinical results and improved survivorship. The present study analyzed the clinical and radiographic results of the first 240 total ankle arthroplasties performed by the authors with one of these new three-component prostheses.

METHODS

Two hundred and forty consecutive primary total ankle arthroplasties were performed in 233 patients (115 women and 118 men; mean age, 61.6 years) between November 2003 and October 2007 with the Mobility prosthesis. Intraoperative and postoperative complications, reoperations, and failures were recorded. The American Orthopaedic Foot & Ankle Society hindfoot score and a visual analog scale score assessment of pain were determined at each follow-up visit. Range of ankle motion was measured on functional radiographs, and the radiographs were studied to assess component positioning, radiolucencies, new bone formation, and periprosthetic bone cysts.

RESULTS

Two hundred and thirty-three of the arthroplasties were available for follow-up at least one year after surgery. The mean duration of follow-up was 32.8 ± 15.3 months. There were ten intraoperative complications (4.2%) and twenty postoperative complications (8.6%). A reoperation was necessary in eighteen ankles (7.7%). Five arthroplasties (2.1%) failed at a mean of twenty-seven months after surgery. The mean American Orthopaedic Foot & Ankle Society hindfoot score improved from 48.2 to 84.1 points (p < 0.001). The mean pain level decreased from 7.7 to 1.7 points (p < 0.001). The mean total range of ankle motion improved from 19.8° to 21.9° (p < 0.001). The tibial component had a mean of 2.1° of varus and a mean posterior slope of 6.0° relative to the tibial axis. The prevalence of nonprogressive radiolucency ranged from 1.8% to 37.3% in the ten zones surrounding the tibial component, and from 0 to 2.2% in the three zones surrounding the talar component.

CONCLUSIONS

The short-term clinical and radiographic results after Mobility total ankle arthroplasty are encouraging and are at least comparable with those associated with other modern three-component implants. The minimum duration of follow-up of one year is short, and studies with longer follow-up are needed to confirm our findings.

Risk factors for incision-healing complications following total ankle arthroplasty

BACKGROUND

The anterior incision used for the insertion of total ankle arthroplasty systems is at high risk for wound complications, and little has been documented regarding who is at risk for the development of these complications.

METHODS

We conducted a retrospective chart review of 106 total ankle arthroplasties. Independent risk variables, including age, sex, body-mass index, diabetes, smoking, medications, preoperative diagnosis, implant size, tourniquet time, closure method, and anticoagulation status, were recorded. Postoperative office notes were reviewed for wound-related complications. Outcomes were divided into three categories: no complications (uncomplicated wound-healing), minor complications (wounds requiring only local care/oral antibiotics), and major complications (requiring a return to the operating room for treatment). Simultaneously, categorical variables were compared with use of chi-square analysis. Multivariate logistic regression and odds ratio assessment were performed as well.

RESULTS

When patients who had no complications were compared with those who had minor complications, a history of diabetes was the only variable that was identified as resulting in a significant risk increase (p = 0.04). When patients who had no wound complications or minor wound complications were compared with those who had major wound complications, female sex, a history of corticosteroid use, and underlying inflammatory arthritis were all associated with increased risk. Multivariate logistic regression demonstrated underlying inflammatory arthritis (p = 0.004) to be the only significant risk factor for major wound complications, with an odds ratio demonstrating a 14.03 times increased risk of requiring reoperation.

CONCLUSIONS

We recommend that caution be used when selecting and educating patients with inflammatory arthritic conditions who are potential candidates for total ankle arthroplasty.

Total ankle prostheses in rheumatoid arthropathy: Outcome in 52 patients followed for 1-9 years

BACKGROUND AND PURPOSE

The first generations of total ankle replacements (TARs) showed a high rate of early failure. In the last decades, much progress has been made in the development of TARs, with the newer generation showing better results. We evaluated TARs implanted with rheumatoid arthritis (RA) or juvenile inflammatory arthritis (JIA) as indication.

PATIENTS AND METHODS

58 total ankle prostheses (Buechel-Pappas and STAR type) were implanted in patients with RA (n = 53) or JIA (n = 5) in 54 patients (4 bilateral). After a mean followup of 2.7 (1-9) years, all patients were reviewed by two orthopedic surgeons who were not the surgeons who performed the operation. Standard AP and lateral radiographs were taken and a Kofoed ankle score was obtained; this is a clinical score ranging from 0-100 and consists of sub-scores for pain, disability, and range of motion.

RESULTS

2 patients died of unrelated causes. Of the 52 patients who were alive (56 prostheses), 51 implants were still in place and showed no signs of loosening on the most recent radiographs. The mean Kofoed score at follow-up was 73 points (SD 16, range 21-92). 4 patients showed a poor result (score < 50) with persistent pain for which no obvious reason could be found. 5 implants were removed, 4 because of infection and 1 because of aseptic loosening.

INTERPRETATION

Medium-term results of the STAR and BP types of TAR in RA were satisfactory. The main reason for failure of the implant was infection.

In vivo kinematics of the salto total ankle prosthesis

BACKGROUND

Recent technological advancements in total ankle arthroplasty (TAA) have included the introduction of the mobile bearing concept. This bearing has several advantages, but researchers have questioned whether or not increased mobility sacrifices joint stability or durability of the implant. The present study evaluated the kinematics of this type of prosthesis implanted in patients.

MATERIALS AND METHODS

Fluoroscopy and 3D-to-2D registration techniques were used to determine the in vivo kinematics for 20 TAA subjects performing two activities: gait and step-up. The motion of the prostheses was described in terms of clinical rotations and as rotation about the helical (screw) axis. Then, the anterior-posterior translation and axial rotation of the mobile bearing insert were determined.

RESULTS

Among the clinical rotations, the dorsi-/plantarflexion was the most dominant, revealing the greatest pattern change and the largest magnitude. During gait, the orientation of the prosthetic components changed smoothly from plantarflexion to dorsiflexion. The average range of this motion was 9.2 degrees. For step-up activity, the range was 8.0 degrees. However, between 33% and 66% of stance phase, the talar component's orientation changed from dorsiflexion to plantarflexion. The average absolute range of anterior-posterior translation of the mobile bearing insert was 1.5 mm and 2.3 mm for gait and step-up, respectively.

CONCLUSION

These measured translations were relatively small and may suggest that the rotational portion of the motion was more dominant than translational and provided sufficient mobility.

Posttraumatic ankle arthritis: an update on conservative and surgical management

This manuscript offers current information regarding the examination, conservative treatment, and surgical treatment for individuals with posttraumatic arthritis. Although inflammatory and osteoarthritis can occur, posttraumatic arthritis is the most common form of arthritis to affect the ankle. Posttraumatic ankle arthritis occurs in a generally younger, active population. It is radiographically characterized by an asymmetrical degenerative process and may be associated with a history of trauma, instability, and/or lower extremity malalignment. When choosing between conservative/nonoperative versus surgical intervention, the extent of subchondral bone exposed and the time over which the arthritis has developed are factors that should be considered. The role and effectiveness for conservative treatment, such as medication, patient education, shoe modification, bracing, stretching, mobilization, strengthening, and symptom management, needs to be further determined. Surgical procedures for posttraumatic ankle arthritis can include distraction arthroplasty, arthrodesis, or total ankle arthroplasty. Unlike the relatively new procedure of distraction arthroplasty, the outcomes for arthrodesis have been well defined. Arthrodesis generally has a good outcome, but its limitations have been recognized. These limitations include the extended time required to achieve fusion, potential for nonunion, arthritis developing in adjacent joints, leg length discrepancy, malalignment, chronic edema, symptoms due to the hardware, stress fractures, and continued pain. While first generation total ankle arthroplasty led to poor results, advancements in prosthetic design and surgical technique have revived optimism regarding total ankle arthroplasty as an alternative to arthrodesis. The key for the future of total ankle arthroplasty may not be related to the development of newer ankle components but rather in refining the criteria to determine who would best benefit from joint replacement versus fusion.

Buechel-Pappas total ankle prosthesis: results in patients 5 to 7 years postimplantation

This article presents a sampling of patients who are 5 to 7 years post-Buechel-Pappas total ankle replacement. The implantations were performed during the Buechel-Pappas clinical trials in the United States that began in November 1998. The author implanted 78 patients from 12 states who were 15 to 83 years old at the time of surgery; 85% or more of these patients have minimal pain or are pain-free despite the appearance of the prosthesis on radiographs.

The management of failed ankle replacement

Advances in the design of the components for total ankle replacement have led to a resurgence of interest in this procedure.

Between January 1999 and December 2004, 16 patients with a failed total ankle replacement were referred to our unit. In the presence of infection, a two-stage salvage procedure was planned. The first involved the removal of the components and the insertion of a cement spacer. Definitive treatment options included hindfoot fusion with a circular frame or amputation. When there was no infection, a one-stage salvage procedure was planned. Options included hindfoot fusion with an intramedullary nail or revision total ankle replacement. When there was suspicion of infection, a percutaneous biopsy was performed. The patients were followed up for a minimum of 12 months.

Of the 16 patients, 14 had aseptic loosening, five of whom underwent a revision total ankle replacement and nine a hindfoot fusion. Of the two with infection, one underwent fusion and the other a below-knee amputation. There were no cases of wound breakdown, nonunion or malunion.

Management of the failed total ankle replacement should be performed by experienced surgeons and ideally in units where multidisciplinary support is available. Currently, a hindfoot fusion appears to be preferable to a revision total ankle replacement.

Eight-year results of a minimally constrained total ankle arthroplasty

BACKGROUND

Few studies have reported the intermediate to long-term results of minimally constrained total ankle replacements. The purpose of this study was to investigate the efficacy and safety of a minimally constrained total ankle prosthesis in a select low-demand patient population.

METHODS

We reviewed a consecutive series of patients with rheumatoid arthritis who underwent a Buechel-Pappas total ankle replacement (BP TAR) between 1990 to 1997. Thirty-one ankle arthroplasties were performed in 23 patients with rheumatoid arthritis. One patient was lost to followup (deceased) and two ankles that failed resulted in fusion (overall survivorship - 93%). This left 28 ankles (21 patients) that were re-evaluated clinically and radiographically with an average followup of 8.3 (range 5.0 to 12.2) years. Preoperative and postoperative ranges of motion were measured and AOFAS hindfoot scores were calculated. Recent weightbearing radiographs were reviewed for evidence of component subsidence, radiolucent lines, and osteolysis.

RESULTS

In 25 of 28 ankles (89%), patients were completely satisfied with the result of their ankle replacement and rated their pain as only mild to none; three (11%) patients were dissatisfied. Radiographic analysis revealed stable, well-positioned implants with evidence of biologic ingrowth in 23 ankles (82%), while five implants were interpreted as being at risk for impending failure because of marked tibial or talar component subsidence (18%). Component subsidence did not correlate with the presence or absence of radiolucent lines. Only one ankle demonstrated clear evidence of osteolysis. Ten intraoperative medial malleolar fractures occurred (32% of ankles) during implantation of the prosthesis, though in only one did this adversely affect patient outcome. Nine postoperative complications (29%) occurred; four wound dehiscences, four stress fractures, and one medial malleolar nonunion.

CONCLUSIONS

Improvements in prosthetic design such as cementless fixation and decreased constraint appear to make total ankle arthroplasty a more predictable procedure over this period of followup. Despite a variety of complications, we are encouraged by the intermediate-term results in a select low-demand arthritic population.

Total ankle arthroplasty: a review of 11 current ankle implants

Introduced in the early 1970s, total ankle arthroplasty offered patients with debilitating ankle arthritis reduction in pain and almost normal mobility at the ankle joint. The idea of replacing an arthritic ankle joint with a mobile ankle prosthesis was originally welcomed to replace ankle arthrodesis. Unfortunately, high failure rates of first-generation implants led many surgeons in the United States to recommend ankle arthrodesis as the best alternative. An improved understanding of ankle joint mechanics, implant material and design, and surgical technique has led to the development of several second-generation implants that are being used successfully throughout the world. As short-term, mid-term, and long-term results continue to be published, there has been a momentous change in the outlook of total ankle arthroplasty as a viable option to ankle arthrodesis.

Total ankle replacement in patients with rheumatoid arthritis

Patients with rheumatoid arthritis commonly experience involvement of the ankle and hindfoot. Severe pain and functional limitations may develop as a result of tibiotalar arthritis, requiring surgical treatment. The advantages of total ankle arthroplasty over ankle arthrodesis include preservation of motion and decreased stresses on the midfoot and subtalar joints. Previous experience with early design ankle replacements revealed high complication rates and as much as 75% of component loosening. Modern ankle implants have been designed to achieve uncemented fixation with less articular constraint. Patients with rheumatoid arthritis who had total ankle replacement using two different types of second-generation ankle implants were examined clinically and radiographically. The average postoperative American Orthopaedic Foot and Ankle Society ankle-hindfoot score was 81 of a possible 100, at a mean of 6.4 years after surgery. Radiographically, 88.5% of implants were stable without evidence of subsidence at a mean of 6.3 years. Three tibial components had subsided at an average of 7 years. There was evidence of tibial osteolysis with the Buechel Pappas Low Contact Stress implant in 11.5% of patients. Total ankle replacement in patients with rheumatoid arthritis, using a second-generation prosthesis, can provide reliable relief of pain and good functional results at intermediate-term followup, although the incidence of osteolysis warrants close followup.

Complications and failure after total ankle arthroplasty

BACKGROUND

Second-generation total ankle arthroplasty has been reported to have good intermediate-term results. The purpose of the present study was to report on the cause and frequency of reoperation and failure after total ankle arthroplasty and to determine demographic and clinical predictors of reoperation and failure.

METHODS

Three hundred and six consecutive primary total ankle arthroplasties were performed with use of the DePuy Agility Total Ankle System between 1995 and 2001. At a mean of thirty-three months after the arthroplasty, we retrospectively reviewed the records with regard to patient age, gender, the indications for the index procedure, adjuvant procedures, the timing and frequency of reoperation, and the indications for and the type of reoperations performed. Kaplan-Meier analysis was performed to determine the rate of prosthetic survival, and Cox regression analysis was performed to determine predictors of reoperation and failure.

RESULTS

Eighty-five patients (28%) underwent 127 reoperations (involving 168 procedures) after primary total ankle arthroplasty. The most common procedures at the time of reoperation were débridement of heterotopic bone (fifty-eight), correction of axial malalignment (forty), and component replacement (thirty-one). Eight patients underwent below-the-knee amputation. Age was found to be the only significant predictor of reoperation and failure after total ankle arthroplasty. The five-year survival rate with reoperation as the end point was 54%. The five-year survival rate with failure as the end point was 80% for all patients and 89% for patients who were more than fifty-four years of age. The prosthesis could not be salvaged in nine ankles (2.9%); the inability to salvage the prosthesis was most often due to loosening or infection.

CONCLUSIONS

We noted a relatively high rate of reoperation after total ankle arthroplasty with this second-generation device. Younger age was found to have a negative effect on the rates of reoperation and failure. Most prostheses could be salvaged; however, the functional outcome of this procedure is uncertain.

Challenges in total ankle arthroplasty

In the past, total ankle arthroplasty was largely abandoned due to poor survivorship most often caused by loss of bone support. High complication rates were also reported. Despite this, there is renewed interest in ankle arthroplasty and encouraging results are seen in survivorship with midterm follow-up. The procedure, however, remains more challenging than total hip or total knee arthroplasty. With the limited soft tissue envelope, wound problems are not uncommon. Forces at the ankle are very large and yet the surface area for prosthetic support is small. Therefore, fixation can be more difficult. The strongest bone can be eccentric at the distal tibia. The tibial prosthesis can, therefore, tend to settle into the softer bone often laterally. Polyethylene needs to be sufficiently thick to maintain its integrity but that requires a larger bone resection, which weakens bone support. Polyethylene failure or wear leads to the majority of failures in hip and knee arthroplasty. There is a need for further basic science research in total ankle arthroplasty. The lessons learned from other arthroplasty should be considered in ankle arthroplasty design.

Surgeon training and complications in total ankle arthroplasty

BACKGROUND

This study assessed the problems with initial use of ankle arthroplasty by surgeons who were trained by observing the surgeon/inventor (group I), who have completed a structured, hands-on surgical training course (group II), or who were trained during a 1-year foot and ankle fellowship (group III).

MATERIALS AND METHODS

The perioperative records of the first 10 cases of nine surgeons were reviewed. We evaluated the 6-month-postoperative standing mortise and lateral radiographs for evidence of syndesmosis union and accuracy of tibial component implantation. Three surgeons were each in group I, group II, and group III. Average patient age at time of surgery was similar. Ankle arthritis was classified as rheumatoid arthritis (RA) or osteoarthritis (OA) as follows: group I (7 RA, 23 OA), group II (7 RA, 23 OA), and group III (3 RA, 27 OA).

RESULTS

In group I, there were nine intraoperative complications, four postoperative wound dehiscences, and three postoperative deep infections. Radiographic evaluation of the 26 cases with adequate postoperative roentgenograms revealed that 10/26 (38%) had a delayed union of the syndesmosis. In group II, there were six intraoperative complications and two postoperative wound problems: an early anterior wound problem and a delayed lateral wound breakdown. Radiographic evaluation of the 26 cases with adequate postoperative roentgenograms revealed that 13/26 (50%) had a delayed union of the syndesmosis. In group III, there were four intraoperative complications and four postoperative wound problems--all healed with local supportive care with one requiring lateral hardware removal. Radiographic evaluation of the 26 cases with adequate postoperative roentgenograms revealed that 5/30 (17%) had a delayed union of the syndesmosis. The initial series from these three groups are statistically indistinguishable with respect to rates of complications, revisions, or malalignment.

CONCLUSION

No identified training method had a statistically demonstrable positive impact on preparing surgeons for performing total ankle replacement. Some of these findings are likely generic for total ankle replacements and not restricted to any class or design of implant. Surgeon initial use of total ankle replacement needs to be done with caution and serious consideration.

Total ankle arthroplasty: a historical perspective

The ideal total ankle prosthesis has yet to be determined, but much has been learned from early experiences in ankle arthroplasty. Modern implants are typically more respectful of anatomic concerns, have found a happy medium of constraint, and have found novel approaches to decrease interface stress. Biologic fixation has improved on cemented results. Surgical techniques and understanding of wound healing and ligamentous deficiency have advanced. Current series still have varied results, and longer-term follow-up is needed. Despite this, some modern ankle replacements represent significant progress, with improved results and survival challenging those of arthrodesis. Further, benefits of preserved motion and avoidance of foot arthritis outstrip this traditional "gold standard." Today, tempered enthusiasm for the future of total ankle arthroplasty is again apparent. A diverse, international effort is underway to create a lasting joint implant. Building on the lessons of the past, different investigators in different countries, using markedly different prostheses, continue to work toward this goal.

Ankle biomechanics

The developers of a successful prosthetic implant for ankle replacement must consider the biomechanical properties that are unique to this complex joint. The prosthesis needs to provide structural support while allowing for motion in the sagittal, transverse, and coronal planes. Although the design must conform to and function within the soft tissue constraints of the ankle, it is only a component of the overall success. Paying attention to leg alignment and meticulous soft tissue balancing is essential to a satisfactory outcome.

Long-term results following ankle arthrodesis for post-traumatic arthritis

BACKGROUND

Ankle arthrodesis is considered by many to be the standard operative treatment for end-stage ankle arthritis; however, the long-term effect of ankle arthrodesis on other lower-extremity joints remains largely unknown. The purpose of this study was to perform a clinical and radiographic review to determine the effect of ankle arthrodesis on the development of osteoarthritis in other lower-extremity joints.

METHODS

Twenty-three patients who had had an isolated ankle arthrodesis for the treatment of painful posttraumatic arthritis of the ankle were followed for a mean of twenty-two years (range, twelve to forty-four years) after the operation. Each completed standardized, self-reported outcome questionnaires (the Foot Function Index, Western Ontario and McMaster University Osteoarthritis Index [WOMAC], and Short Form-36 [SF-36]), was examined clinically by two of the investigators, and underwent complete radiographic examination of the knee, ankle, and foot bilaterally. The radiographic grade of osteoarthritis was determined for each joint, and the levels of overall activity limitation, pain, and disability were determined for each patient from the clinical findings and questionnaire information.

RESULTS

Osteoarthritis of the ipsilateral subtalar (p<0.0001), talonavicular (p<0.0001), calcaneocuboid (p<0.0001), naviculocuneiform (p = 0.0012), tarsometatarsal (p = 0.0009), and first metatarsophalangeal joints (p = 0.0012) was consistently more severe than the osteoarthritis of those joints on the contralateral side. Osteoarthritis did not develop more frequently in the ipsilateral knee or lesser metatarsophalangeal joints than it did on the contralateral side. Significant differences between the two sides were found with regard to overall activity limitation (p<0.0001), pain (p<0.0001), and disability (p<0.0001), with the involved side consistently more symptomatic.

CONCLUSIONS

To our knowledge, the present series represents the longest follow-up study of ankle arthrodesis to date. Our cohort of patients all had isolated post-traumatic ankle arthritis, and each underwent a successful isolated ankle arthrodesis. At a mean of twenty-two years, the majority of the patients had substantial, and accelerated, arthritic changes in the ipsilateral foot but not the knee. They were often limited functionally by foot pain. Although ankle arthrodesis may provide good early relief of pain, it is associated with premature deterioration of other joints of the foot and eventual arthritis, pain, and dysfunction.

A determination of ankle kinematics using fluoroscopy

In vivo weight-bearing studies utilizing dynamic video fluoroscopy have been shown to offer an accurate and reproducible method for determining the kinematics of a joint. The purpose of this study was to evaluate translational and rotational motions of the distal tibia relative to the talus in the sagittal and frontal planes. Ten subjects, each having a normal ankle and a total ankle arthroplasty on the opposite side (Buechel-Pappas Total Ankle, Endotec, South Orange, NJ), were studied under in vivo, weight-bearing conditions using video fluoroscopy. All ten subjects were judged to have a successful arthroplasty without demonstrable pain or ligament instability. Under weight-bearing conditions, each subject performed successive motions moving from maximum dorsiflexion to plantarflexion. At maximum dorsiflexion, both the normal and implanted ankles had similar sagittal midline talar contact positions but with plantar flexion, implanted ankles had increased posterior talar contact. Contact points on the distal tibia revealed that the lateral surface contacted at the midline or posterior throughout range-of-motion with minimal translation. The medial distal tibia contacted the talus posterior on plantarflexion and often moved anteriorly with dorsiflexion. This translation described relative external rotation of the distal tibia on plantar flexion and internal rotation on dorsiflexion. The measured distances were larger for the implanted ankles with higher variability. The average range-of-motion was 37.4 degrees for normal ankles and 32.3 degrees for implanted ankles. This study defines the normal kinematic rotational and translational motions of the ankle joint by accurately describing the three dimensional joint orientations. The implanted ankles experienced rotational and translational motions but had contacts more posterior, possibly related to surgical technique or alterations of ligamentous tension.

Total ankle replacement revisited

The surgical treatment of painful, end-stage ankle arthritis includes ankle arthrodesis and total ankle replacement. In the past decade, total ankle replacement has become a viable alternative to ankle arthrodesis. Modern implant designs either involve a syndesmosis fusion and resurfacing of the medial and lateral recesses of the ankle joint or the use of a 3-component, mobile bearing implant. In limited clinical series, the early results of both these prosthetic design approaches are encouraging. In selected patients, ankle arthroplasty is an effective approach to relieving pain and improving function. The purposes of this paper are to review the clinical results from total ankle replacement and ankle arthrodesis; discuss indications, contraindications, design features, postoperative rehabilitation, and initial results for the major current total ankle designs; and present concepts for future total ankle development. In particular, this article explores the advantages and concerns with 2 prevalent but different design approaches. It also discusses future directions for total ankle replacement.