Correlation of Physical Performance and Patient-Reported Outcomes Following Total Ankle Arthroplasty

Outcome measures after foot and ankle surgery: A Systematic Review

BACKGROUND

Research on outcomes measures after foot and ankle surgery is limited and methodological quality is not always assessed. We aimed to evaluate the measurement properties of patient-related outcome measures used in patients after foot- and ankle surgery.

METHODS

A Medline, Embase and Web of Sciences systematic review was performed including dates from 2000 up to April 2022. Inclusion criteria were foot and/or ankle surgery, described outcome(s) and it's assessed measurement properties. Methodological quality assessment was performed using the NOS-scale and the COSMIN-criteria.

RESULTS

143 studies (n = 18383) were included for final review, 82 about PROMs, 61 about clinical outcomes. A total of 23 different PROMs were evaluated, with a positive result in all measurement properties for the FAOS. There were positive results too for most measurement properties of the LEFS and the MOXFQ. Most clinical outcomes were radiological measures, with a high reliability for most measurements on plain radiographs and CT-scans.

CONCLUSIONS

To monitor foot and ankle outcome and evaluate treatment, we recommend the FAOS as the most suitable foot and ankle PROM.

LEVEL OF CLINICAL EVIDENCE

2.

Gait stability improves following unilateral total ankle arthroplasty

End-stage ankle arthritis is often treated surgically by total ankle arthroplasty (TAA) due to its potential to improve gait through increased joint range of motion and reduce pain. However, TAA's effect on gait stability is not well understood. This study explores the impact of TAA on gait stability, measured by Margin of Stability (MoS), in 148 patients with end-stage ankle arthritis. Kinematic data were collected pre-operatively, at 1-year post-op, and at 2-years post-op and the MoS was determined at heel strike and midstance for the anteroposterior (MoSAP) and mediolateral (MoSML) directions. A linear mixed effects model including gait speed as a factor was used to assess the effects of limb, session, and their interaction on outcome measures. A significant interaction (p < 0.002) between limb (surgical, nonsurgical) and session (pre-op, 1-year post-op, 2-years post-op) was identified for each MoS variable of interest. Cumulatively, our results suggest that the nonsurgical limb, MoSAP at heel strike and MoSML at midstance improved (increased) as time from surgery increased. These results suggest patients developed a compensatory movement pattern to navigate surgical limb single support. TAA reduces this compensation improving side-to-side symmetry, while not fully restoring symmetry by 2-years post-op. These results indicate that TAA could improve gait stability in patients with end-stage ankle arthritis, but further work is needed to understand the impact of TAA on altering fall risk.

Clinical Outcomes and Registry Data in Total Ankle Arthroplasty

Total ankle arthroplasty (TAA) is an effective treatment for end-stage ankle arthritis consistently demonstrating good to excellent outcomes, even when considering factors such as deformity, patient age, bilaterality, and arthritis etiology. There is little consensus in the literature with regard to preferred patient-reported outcome metrics (PROMs) for assessing outcomes, although all metrics generally improve following TAA. Several countries have successful registries to track longevity of TAA in populations; however, PROMs are generally not successfully tracked in registries. A trend toward consensus on outcome metrics and collaborative registries is warranted to optimize patient selection and outcomes in TAA.

The effect of total ankle arthroplasty on mechanical energy exchange

Total ankle arthroplasty (TAA) is a common surgical solution for patients with debilitating arthritis of the ankle. Prior to surgery patients experience high levels of pain and fatigue and low mechanical energy recovery. It is not known if TAA restores healthy levels of mechanical energy recovery in this patient population. This study was designed to determine whether mechanical energy recovery was restored following TAA. Ground reaction forces during self-selected speed walking were collected from patients with symptomatic, unilateral ankle arthritis (N = 29) before and one and two years after primary, unilateral TAA. The exchange of potential (PE) and kinetic (KE) energy was examined, and direction of change (%congruity) and energy exchange (%recovery) between the two curves was calculated, with those subjects with low congruity experiencing high energy recovery. Linear regressions were used to examine the impact of walking speed, congruity, and amplitude of the center of mass (COM) displacement on %recovery, while ANOVA and ANCOVA models were used to compare energy recovery and congruity across the three time points. Gender, BMI, and age at surgery had no effect in this study. TAA improved walking speed (p = 0.001), increased energy recovery (p = 0.020), and decreased congruity (p = 0.002), and these levels were maintained over at least two years. Differences in congruity were independent of walking speed. In some patients, especially those who are severely debilitated by ankle arthritis, TAA is effective in restoring mechanical energy recovery to levels similar to an asymptomatic population of a similar age recorded by other studies.

Patients with unilateral ankle arthritis have decreased discrete and time-series limb symmetry compared to healthy controls

Patients with ankle arthritis (AA) have side-to-side limb differences at the ankle and in spatiotemporal measures; however, the degree of symmetry between limbs has not been compared to a healthy population. The purpose of this study was to determine differences in limb symmetry during walking for discrete and time-series measures when comparing patients with unilateral AA to healthy participants. Thirty-seven AA and 37 healthy participants were age, gender, and body mass index matched. Three-dimensional gait mechanics and ground reaction force (GRF) were captured during four to seven walking trails. GRF and hip and ankle mechanics were extracted bilaterally for each trial. The Normalized Symmetry Index and Statistical Parameter Mapping were used to assess discrete and time-series symmetry, respectively. Discrete symmetry was analyzed using linear mixed-effect models to determine significant differences between groups (α = 0.05). Compared to healthy participants, patients with AA had decreased weight acceptance (p = 0.017) and propulsive (p < 0.001) GRF, ankle plantarflexion (p = 0.021), ankle dorsiflexion (p = 0.010), and ankle plantarflexion moment (p < 0.001) symmetry. Significant regions of difference were found between limbs and groups throughout the stance phase for the vertical GRF force (p < 0.001), the ankle angle during push-off (p = 0.047), the plantarflexion moment (p < 0.001), and the hip extension angle (p = 0.034) and moment (p = 0.010). Patients with AA have decreased symmetry in the vertical GRF and at the ankle and hip during the weight acceptance and propulsive portions of the stance phase. Therefore, clinicians should try a non improving symmetry focusing on changing hip and ankle mechanics during the weight acceptance and propulsive phases of gait.

Ankle plantar flexor muscle performance and patient reported outcomes in people following total ankle arthroplasty

BACKGROUND

The purpose of this study was to prospectively evaluate ankle power generation during gait in people with total ankle arthroplasty, and examine the relationships between postoperative plantar flexor strength, ankle power, and patient outcomes.

METHODS

Nineteen people with end-stage ankle arthritis who received a total ankle arthroplasty and 19 healthy matched controls participated in this case-control study. Patient reported outcomes included a region specific measure of foot function and a generic measure of physical function. Gait speed was recorded with the 6-min walk test. Isokinetic plantar flexor strength was measured with an instrumented dynamometer. Motion capture and force plate data were used to calculate peak ankle power generation during walking. Paired or independent t-tests were used to compare ankle power across time and between groups, respectively. Bivariate correlations were performed to examine the interplay of postoperative strength, ankle power, gait speed, and patient reported outcomes.

FINDINGS

Ankle power was not different between the preoperative and 6-month postoperative time points (d = 0.20). Six-month postoperative ankle power was less than controls (d = 1.32). Strength, ankle power, and gait speed were directly correlated in the patient group 6-months postoperatively (r or ρ ≥ 0.47). Six-month postoperative strength and ankle power were directly correlated to select 2-year patient reported outcomes (both ρ = 0.54).

INTERPRETATION

Lower than normal 6-month postoperative ankle power, which was correlated to strength, gait speed, and longer-term patient reported outcomes, suggests efforts toward improving ankle plantar flexor muscle performance may improve patient outcomes.

Physical function measurement in older long-term cancer survivors

OBJECTIVE

To establish reliability, validity, and minimal detectable change in measures of function in older long-term cancer survivors.

METHODS

Older cancer survivors were recruited to perform functional measures; 5 Times Sit-to-Stand (5xSTS), 30-second Timed Chair Rise (30sTCR), Short Physical Performance Battery (SPPB), Physical Performance Test-7 (PPT-7). Two testing sessions were completed two weeks apart. Test-retest reliability was examined using the intraclass correlation coefficient (ICC2,1), convergent and discriminant validity using Spearman's rho and Minimal Detectable Change (MDC95) was calculated.

RESULTS

Forty-seven older long-term cancer survivors participated. Test-retest reliability was good for 5xSTS (ICC2,1=0.86), 30sTCR (ICC2,1=0.89), and SPPB (ICC2,1=0.85) and poor for PPT-7 (ICC2,1=0.48). Both convergent and discriminant validity was established.

CONCLUSIONS

SPPB, 5xSTS, and 30sTCR are reliable and valid tools to measure function in older long-term cancer survivors. MDC95 values were larger than those reported in geriatrics and should be interpreted with caution. Residual effects of cancer treatment, comorbidity, and physical inactivity may contribute to decreased physical function in older long-term cancer survivors, therefore valid and reliable measures like SPPB and the timed chair rise tests should be used objectively measure function throughout the survivorship spectrum.

Outcome Reporting in Total Ankle Arthroplasty: A Systematic Review

Total ankle arthroplasty is an increasingly utilized treatment for ankle arthritis due to decreasing failure rates and improved outcomes. However, the literature on this procedure remains heterogeneous with large variability in outcome reporting methods. PRISMA guidelines were used to systematically review outcome reporting measures used in prospective studies and randomized control trials on total ankle arthroplasty published in 15 high-impact journals between Jan 1, 2009-May 1, 2020. A total of 43 studies were included and outcome measures were grouped into seven categories: pain, subjective function, patient satisfaction, complications, objective function, implant survivorship, and imaging. The most common topic of study was implant design followed by differences in outcomes when comparing total ankle arthroplasty and arthrodesis. The most commonly reported outcome measure was post-surgical complications. No study reported on all seven categories, while 22 (51.2%) studies reported on four or more. Subjective measures had significant variability with fifteen different Patient Reported Outcome Measures used across the studies. While the included studies were quite comprehensive, there was little consistency in reporting outcomes after total ankle arthroplasty. With improving outcomes and techniques in total ankle arthroplasty, and thus an expected increase in utilization and number of published studies, efforts should be made to use commonly employed outcome reporting methods to facilitate comparison of results across studies.

Effect of Gender Differences on Patient-Reported Outcomes and Complications in Total Ankle Replacement

BACKGROUND

The purpose of this study was to evaluate gender differences in patient outcomes and complications following total ankle replacement (TAR).

METHODS

Consecutive patients who underwent primary TAR from July 2007 through May 2016 were prospectively followed and retrospectively reviewed. Demographic, operative, patient-reported outcomes (PROs), and complication data were collected and analyzed. PROs included the visual analog scale (VAS), 36-Item Short-Form Health Survey (SF-36), American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scale, and Short Musculoskeletal Function Assessment (SMFA). A total of 475 patients were evaluated, including 248 males (52.2%) and 227 females (47.8%) with an average of 56.8 months follow-up.

RESULTS

Women were more likely to have inflammatory arthritis (13.7% vs 2.8%; P < .01) and significantly worse preoperative SF-36 total, SF-36 mental health component, AOFAS total, AOFAS pain, SMFA function, and SMFA bother scores (all P < .05). Both genders demonstrated significant improvement in PROs at 1, 2, and 5 years. The magnitude of improvement was similar between genders for all PROs (all P < .05) with the exception of SF-36 physical function, which was greater in men. Females underwent more nonrevision reoperations (32.2% vs 22.6%; P = .0191), but there was no significant difference in failure rates (male 7.3% vs female 3.5%; P = .07). The reoperation and failure rates at 2 years postoperation were 10.1% and 1.6% for men and 18.5% and 0.9% for women, respectively.

CONCLUSION

Women undergoing TAR were more likely to have worse preoperative PROs and higher rates of nonrevision reoperations, which remains true when controlling for their increased incidence of inflammatory arthritis. However, women reported similar improvements in PROs and had similar prosthetic survival rates as men. Increased understanding of these disparities, combined with gender-based interventions, may further advance patient outcomes.

LEVEL OF EVIDENCE

Level III, therapeutic, retrospective comparative series.

Correlation of Patient-Reported Outcomes With Physical Function After Total Ankle Arthroplasty

BACKGROUND

Total ankle arthroplasty (TAA) is successful by both subjective patient-reported outcome measures (PROMs) and objective functional improvements of gait. Each is reproducible and valid, but they are entirely distinct methods. This study investigated the correlation between subjective and objective outcomes of TAA.

METHODS

Seventy patients underwent gait analysis preoperatively and 1 year after TAA. The 36-Item Short-Form Health Survey (SF-36) and visual analog score (VAS) for pain and American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Scores were recorded at each interval. A Student t test, a multivariate regression, and a Pearson correlation coefficient were used to measure the correlation between parameters of gait and PROMs.

RESULTS

Patients had statistically significant improvements in gait velocity, total range of motion (ROM), maximum plantarflexion, ankle power, and SF-36 Physical, VAS, and AOFAS scores. The SF-36 Physical score had a moderate positive correlation with preoperative walking speed, step length, and ankle power and postoperative walking speed and ankle power. No correlation between VAS score and function was detected. The AOFAS score had a moderate positive correlation with postoperative walking speed, step length, and ankle power, and improvement in walking speed, cadence, and ankle power.

CONCLUSION

Statistically significant correlations were found between numerous preoperative and postoperative comparisons of PROMs and the AOFAS score with the objective biomechanical outcomes of gait. Walking speed and ankle push-off power correlated most with patient perceptions of function and improvement, while pain and ROM did not. Subjective PROMs and objective biomechanical outcomes were complementary in the assessment of surgical outcomes and, combined, helped to address the dilemma of the confounding effect of other lower extremity pathologies on PROMs.

LEVEL OF EVIDENCE

Level III, comparative series.

Timeline for maximal subjective outcome improvement following total ankle arthroplasty

BACKGROUND

Maximal medical improvement (MMI) establishes the timepoint when patients no longer experience clinically significant improvements following surgery. The purpose of this investigation is to establish when patients achieve MMI following total ankle arthroplasty (TAA) through the use of patient reported outcome measures (PROMs).

METHODS

A systematic review to identify studies on TAA which reported consecutive PROMs for two years postoperatively was performed. Pooled analysis was done at 6 months, 12 months, and 24 months. Clinically significant improvement was defined as improvement between time intervals exceeding the minimal clinically important difference.

RESULTS

Twelve studies and 1514 patients met inclusion criteria. Clinically significant improvement was seen up to 6 months postoperatively in both the American Orthopaedic Foot and Ankle Society Ankle Hindfoot Score and Visual Analog Scale scoring systems. The Short Musculoskeletal Function Assessment Dysfunction and Bother subsections showed maximal clinically significant improvement by 1 year postoperatively.

CONCLUSION

Following TAA, MMI is seen by one year postoperatively. Physicians may allocate the majority of resources within the first year when most of the improvement is perceived. This data may help inform preoperative counseling as it establishes a timeline for MMI.

LEVEL OF EVIDENCE

IV.

Physical Performance Tests Provide Distinct Information in Both Predicting and Assessing Patient-Reported Outcomes Following Lumbar Spine Surgery

STUDY DESIGN

Secondary analysis of randomized controlled trial data.

OBJECTIVE

The aim of this study was to examine whether preoperative physical performance is an independent predictor of patient-reported disability and pain at 12 months after lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

Patient-reported outcome measures (PROMs) are commonly used to assess clinical improvement after lumbar spine surgery. However, there is evidence in the orthopedic literature to suggest that PROMs should be supplemented with physical performance tests to accurately evaluate long-term outcomes.

METHODS

A total of 248 patients undergoing surgery for degenerative lumbar spine conditions were recruited from two institutions. Physical performance tests (5-Chair Stand and Timed Up and Go) and PROMs of disability (Oswestry Disability Index: ODI) and back and leg pain (Brief Pain Inventory) were assessed preoperatively and at 12 months after surgery.

RESULTS

Physical performance tests and PROMs significantly improved over 12 months following lumbar spine surgery (P < 0.01). Weak correlations were found between physical performance tests and disability and pain (ρ = 0.15 to 0.32, P < 0.05). Multivariable regression analyses controlling for age, education, preoperative outcome score, fusion, previous spine surgery, depressive symptoms, and randomization group found that preoperative 5-Chair Stand test was significantly associated with disability and back pain at 12-month follow-up. Each additional 10 seconds needed to complete the 5-Chair Stand test were associated with six-point increase in ODI (P = 0.047) and one-point increase in back pain (P = 0.028) scores. The physical performance tests identified an additional 14% to 19% of patients as achieving clinical improvement that were not captured by disability or pain questionnaires.

CONCLUSION

Results indicate that physical performance tests may provide distinct information in both predicting and assessing clinical outcomes in patients undergoing lumbar spine surgery. Our findings suggest that the 5-Chair Stand test may be a useful test to include within a comprehensive risk assessment before surgery and as an outcome measure at long-term follow-up.

LEVEL OF EVIDENCE

3.

Overall Health and the Influence of Physical Therapy on Physical Function Following Total Ankle Arthroplasty

BACKGROUND

The overall health and the importance of physical therapy for people following total ankle arthroplasty (TAA) have been understudied. Our purpose was to characterize the overall health of patients following TAA, and explore the frequency, influence, and patient-perceived value of physical therapy.

METHODS

People who received a TAA participated in this retrospective cohort online survey study. The survey included medical history questions and items from the Patient-Reported Outcomes Measurement Information System (PROMIS) Short Forms. Seven PROMIS domains, reflecting the biopsychosocial model of care (physical, mental, social), were included to examine participant overall health status in comparison to the general population. Items regarding physical therapy participation (yes/no), number of visits, and perceived value (scale 0-10; 10 = extremely helpful) were also included. Descriptive statistics were generated for participant characteristics, PROMIS domain T scores, and physical therapy questions. The influence of participant characteristics or physical therapy visits on PROMIS domain T scores that scored below the population mean were examined with multiple linear regression or ordinal regression.

RESULTS

The response rate was 61% (n=95). Average postoperative time was approximately 3 years (mean [SD]: 40.0 [35.3] months). Physical function and ability to participate in social roles and activities domain T scores were at least 1 SD below the population mean. Most patients received physical therapy (86%; 17.1 [11.0] visits) and found it helpful (7.2 [3.0]). Participant characteristics were minimally predictive of physical function and social participation T scores. Number of physical therapy visits predicted physical function T scores (P = .03).

CONCLUSIONS

Most health domain scores approached the population mean. Physical therapy was perceived to have a high value, and greater visits were related to greater physical function. However, lower physical function and social participation scores suggest that postoperative care directed toward these domains could improve the value of TAA and promote overall health.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Methods for Step Count Data: Determining "Valid" Days and Quantifying Fragmentation of Walking Bouts

BACKGROUND

Step count monitors are frequently used in clinical research to measure walking activity. Systematically determining valid days and extracting informative measures of walking beyond total daily step count are among major analytical challenges.

RESEARCH QUESTION

We introduce a novel data-driven anomaly detection algorithm to determine days representing typical walking activity (valid days) and examine the value of measures of walking fragmentation beyond total daily step count.

METHODS

StepWatch data were collected on 230 adults with severe foot or ankle fractures. Average steps per minute (SC), average steps per active minute (SCA), active to sedentary transition probability (ASTP) and sedentary to active transition probability (SATP) were computed for each participant. The joint distribution of these measures was used to identify and eliminate invalid days through a multi-step process based on the support vector machine. The value of SCA, ASTP and SATP beyond SC were assessed by regressing Short Musculoskeletal Functional Assessment (SMFA), a measure of self-reported function, on these measures and quantifying the increase in the adjusted R-squared. In an unsupervised comparison, the total joint variability of SCA, ASTP and SATP was decomposed into the variability explained by SC and the unique variability of these three measures.

RESULTS

Of the 4,448 days in the original data set, 39% were determined invalid. Individuals with higher average SC had higher SCA, lower ASTP and higher SATP. Measures of fragmentation (SCA, ASTP and SATP) explained 25% more of the variability in SMFA compared with SC alone. Approximately 41% of the variability in SCA, ASTP and SATP could not be explained by SC suggesting that these three measures provide unique information about walking patterns.

SIGNIFICANCE

Applying SVM and quantifying fragmentation in walking bouts for step count data can help to more precisely assess activity in clinical studies employing this modality.

Predicting ground reaction and tibiotalar contact forces after total ankle arthroplasty during walking

The motion capture and force plates data are essential inputs for musculoskeletal multibody dynamics models to predict in vivo tibiotalar contact forces. However, it could be almost impossible to obtain valid force plates data in old patients undergoing total ankle arthroplasty under some circumstances, such as smaller gait strides and inconsistent walking speeds during gait analysis. To remove the dependence of force plates, this study has established a patient-specific musculoskeletal multibody dynamics model with total ankle arthroplasty by combining a foot-ground contact model based on elastic contact elements. And the established model could predict ground reaction forces, ground reaction moments and tibiotalar contact forces simultaneously. Three patients' motion capture and force plates data during their normal walking were used to establish the patient-specific musculoskeletal models and evaluate the predicted ground reaction forces and ground reaction moments. Reasonable accuracies were achieved for the predicted and measured ground reaction forces and ground reaction moments. The predicted tibiotalar contact forces for all patients using the foot-ground contact model had good consistency with those using force plates data. These findings suggested that the foot-ground contact model could take the place of the force plates data for predicting the tibiotalar contact forces in other total ankle arthroplasty patients, thus providing a simplified and valid platform for further study of the patient-specific prosthetic designs and clinical problems of total ankle arthroplasty in the absence of force plates data.

Return to Sports and Activity After Total Ankle Arthroplasty and Arthrodesis: A Systematic Review

BACKGROUND

There is no consensus regarding participation in sports and recreational activities following total ankle replacement (TAR) and ankle arthrodesis (AA). This systematic review summarizes the evidence on return to sports and activity after operative management with either TAR or AA for ankle osteoarthritis (OA).

METHODS

A literature search of MEDLINE, EMBASE, CINAHL, and Cochrane Library databases was performed. Risk of bias of included studies was assessed using Methodological Index for Non-Randomized Studies (MINORS) criteria. Included studies reported sport and activity outcomes in patients undergoing TAR and AA, with primary outcomes being the percentage of sports participation and level of sports participation.

RESULTS

Twelve studies met inclusion criteria for analysis. There were 1270 ankle procedures, of which 923 TAR and 347 AA were performed. The mean reported patient age was 59.2 years and the mean BMI was 28 kg/m². The mean follow-up was 43 months. Fifty-four percent of patients were active in sports preoperatively compared with 63.7% postoperatively. The mean preoperative activity participation rate was 41% in the TAR cohort, but it improved to 59% after TAR, whereas the preoperative activity participation rate of 73% was similar to the postoperative rate of 70% in the AA cohort. The most common sports in the TAR and AA groups were swimming, hiking, cycling, and skiing.

CONCLUSION

Participation in sports activity was nearly 10% improved after operative management of ankle OA with TAR and remains high after AA. The existing literature demonstrated a large improvement in pre- to postoperative activity levels after TAR, with minimal change in activity after AA; however, AA patients were more active at baseline. The most frequent postoperative sports activities after operative management of ankle OA were swimming, hiking, cycling, and skiing. Participation in high-impact sports such as tennis, soccer, and running was consistently limited after surgery. This review of the literature will allow patients and foot and ankle surgeons to set evidence-based goals and establish realistic expectations for postoperative physical activity after TAR and AA.

LEVEL OF EVIDENCE

Level III, systematic review.

Management of Posttraumatic Ankle Arthritis: Literature Review

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Outcome after 52 Salto Ankle Prostheses Implanted by a Single Surgeon

While ankle arthrodesis was traditionally the gold standard method of treatment for disabling end-stage ankle arthritis, total ankle replacement (TAR) has been an acceptable alternative. The satisfaction rate of patients with TAR however differs. The purpose of our study is to investigate whether implant survival and results with special emphasis on the satisfaction rate of patients treated with a TAR implanted by a single surgeon were comparable to the literature. This was a retrospective cohort study in a teaching hospital. Data was collected from 52 patients who received a total ankle replacement (TAR) between 05/2002 and 06/2014. The mean follow-up time was 4.2 years (95% CI 3.3 - 5.0). Results showed a high satisfaction rate of 94% and 94% survival of the TAR after 5 years. We conclude that TAR with the Salto prosthesis is, in our hands, a reliable solution for end-stage ankle arthritis, with results comparable to the literature.

Prospective Cohort Study on the Employment Status of Working Age Patients After Recovery From Ankle Arthritis Surgery

BACKGROUND

People who are affected by end-stage ankle arthritis are as disabled as those suffering from arthritis in other main articulations of the lower extremity. Once these patients become unable to perform their job duties, they leave the workforce and require financial aid from government agencies, which represents a considerable economic burden. Regardless of whether arthrodesis or arthroplasty is performed, we hypothesized that patients younger than 55 years at the time of surgery should be able to return to work within 2 years and require less social assistance.

METHODS

Patients from 2002 to 2014 included in the nationwide prospective Ankle Reconstruction Database treated for end-stage ankle arthritis with a total ankle replacement or an ankle arthrodesis and younger than 55 years at the time of surgery were included. This study used a standard preoperative survey (AAOS, SF-36) along with the same survey filled by patients in intervals up to 2 years postoperatively. Their employment status was determined at each time point. Participation in third-party wage assistance programs was recorded. This cohort had 194 patients with an average age of 47.0 ± 7.2 years and was balanced in terms of sex (104 female) and side (94 left).

RESULTS

The employment rate prior to surgery was 56%, which increased to 62% at the 2-year postoperative mark. With regards to worker's compensation, disability, and social security, 20% of patients left all subsidized programs whereas 4% entered at least 1 which is significant (P < .05).

CONCLUSION

The 2-year follow-up after tibiotalar arthrodesis/arthroplasty in patients younger than 55 years showed that significantly more people were able to leave subsidized work assistance programs than enroll in them.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Directing clinical care using lower extremity biomechanics in patients with ankle osteoarthritis and ankle arthroplasty

Ankle osteoarthritis is a debilitating disease with approximately 50,000 new cases per year leading to skeletal deformity, severe and recurrent pain, cartilage breakdown, and gait dysfunction limiting patient mobility and well-being. Although many treatments (total ankle arthroplasty [TAA], ankle fusion [arthrodesis], and ankle distraction arthroplasty) relieve pain, it is not clear that these procedures significantly improve patient mobility. The goal of the research presented here is to summarize what is presently known about lower extremity gait mechanics and outcomes and to quantify the impact of ankle osteoarthritis and TAA have on these measures using an explicitly holistic and mechanistic approach. Our recent studies have explored physical performance and energy recovery and revealed unexpected patterns and sequelae to treatment including incomplete restoration of gait function. These studies demonstrated for the first time the extreme levels and range of gait and balance dysfunction present in ankle osteoarthritis patients as well as quantifying the ways in which the affected joint alters movement and loading patterns not just in the painful joint, but throughout both the ipsilateral and contralateral lower extremity. Through this work, we determined that relieving pain alone through TAA is not enough to restore normal walking mechanics and balance due to underlying causes including limited ankle range of motion and balance deficits leading to long-term disability despite treatment. The results indicate the need to consider additional therapeutic interventions aimed at restoring balance, ankle range of motion, and movement symmetry in order to improve long-term health and function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2345-2355, 2017.

Are There Differences in Gait Mechanics in Patients With A Fixed Versus Mobile Bearing Total Ankle Arthroplasty? A Randomized Trial

BACKGROUND

Total ankle arthroplasty (TAA) is an alternative to arthrodesis, but no randomized trial has examined whether a fixed bearing or mobile bearing implant provides improved gait mechanics.

QUESTIONS/PURPOSES

We wished to determine if fixed- or mobile-bearing TAA results in a larger improvement in pain scores and gait mechanics from before surgery to 1 year after surgery, and to quantify differences in outcomes using statistical analysis and report the standardized effect sizes for such comparisons.

METHODS

Patients with end-stage ankle arthritis who were scheduled for TAA between November 2011 and June 2013 (n = 40; 16 men, 24 women; average age, 63 years; age range, 35-81 years) were prospectively recruited for this study from a single foot and ankle orthopaedic clinic. During this period, 185 patients underwent TAA, with 144 being eligible to participate in this study. Patients were eligible to participate if they were able to meet all study inclusion criteria, which were: no previous diagnosis of rheumatoid arthritis, a contralateral TAA, bilateral ankle arthritis, previous revision TAA, an ankle fusion revision, or able to walk without the use of an assistive device, weight less than 250 pounds (114 kg), a sagittal or coronal plane deformity less than 15°, no presence of avascular necrosis of the distal tibia, no current neuropathy, age older than 35 years, no history of a talar neck fracture, or an avascular talus. Of the 144 eligible patients, 40 consented to participate in our randomized trial. These 40 patients were randomly assigned to either the fixed (n = 20) or mobile bearing implant group (n = 20). Walking speed, bilateral peak dorsiflexion angle, peak plantar flexion angle, sagittal plane ankle ROM, peak ankle inversion angle, peak plantar flexion moment, peak plantar flexion power during stance, peak weight acceptance, and propulsive vertical ground reaction force were analyzed during seven self-selected speed level walking trials for 33 participants using an eight-camera motion analysis system and four force plates. Seven patients were not included in the analysis owing to cancelled surgery (one from each group) and five were lost to followup (four with fixed bearing and one with mobile bearing implants). A series of effect-size calculations and two-sample t-tests comparing postoperative and preoperative increases in outcome variables between implant types were used to determine the differences in the magnitude of improvement between the two patient cohorts from before surgery to 1 year after surgery. The sample size in this study enabled us to detect a standardized shift of 1.01 SDs between group means with 80% power and a type I error rate of 5% for all outcome variables in the study.

RESULTS

This randomized trial did not reveal any differences in outcomes between the two implant types under study at the sample size collected. In addition to these results, effect size analysis suggests that changes in outcome differ between implant types by less than 1 SD. Detection of the largest change score or observed effect (propulsive vertical ground reaction force [Fixed: 0.1 ± 0.1; 0.0-1.0; Mobile: 0.0 ± 0.1; 0.0-0.0; p = 0.0.051]) in this study would require a future trial to enroll 66 patients. However, the smallest change score or observed effect (walking speed [Fixed: 0.2 ± 0.3; 0.1-0.4; Mobile: 0.2 ± 0.3; 0.0-0.3; p = 0.742]) requires a sample size of 2336 to detect a significant difference with 80% power at the observed effect sizes.

CONCLUSIONS

To our knowledge, this is the first randomized study to report the observed effect size comparing improvements in outcome measures between fixed and mobile bearing implant types. This study was statistically powered to detect large effects and descriptively analyze observed effect sizes. Based on our results there were no statistically or clinically meaningful differences between the fixed and mobile bearing implants when examining gait mechanics and pain 1 year after TAA.

LEVEL OF EVIDENCE

Level II, therapeutic study.