The Effect of Deformity and Hindfoot Arthritis on Midterm Outcomes of Ankle Replacement and Fusion

Category: Ankle Arthritis Introduction/Purpose: Background: In 2014, Daniels et al reported the largest prospective comparison of clinical outcomes for Ankle Fusion (AF) and Replacement (TAR). Outcomes were comparable at 5.5 years mean F/U but were not stratified for potentially important factors including ipsilateral: Intra-articular deformity Significant foot deformity Hindfoot arthritis (or prior fusion) These factors define the Type and complexity of end stage ankle arthritis (ESAA) as described by the COFAS Classification. Since the effect of COFAS Type on outcomes is unknown, it remains unknown if TAR or AF might outperform the other in specific Types of ESAA and therefore be preferentially indicated. Purpose: Determine if outcomes for TAR and AF: vary with COFAS Type are different for ankles of the same COFAS Type. Methods: Prospective data from the COFAS multicenter database (3 sites, 5 surgeons) was used to compare outcomes in 890 consecutive non-randomized ankles with minimum 2 year F/U. TAR prostheses utilized were STAR, Hintegra, Infinity and InBone II. AF’s utilized open or arthroscopic techniques. Ankles were stratified according to the COFAS Classification of ESAA (1-isolated ankle arthritis; 2 - intra-articular ankle deformity (varus/valgus); 3 - foot or tibial deformity; 4 - hindfoot arthritis/fusion), creating 8 groups for comparison (AF1 – AF4; TAR1 – TAR4) A linear mixed-effects regression model (adjusted for significant variables identified by univariate analysis: Pre-operative Ankle Osteoarthritis Scale [AOS], age, diabetes status, BMI, surgeon) was used to compare the primary (AOS at latest F/U [AOS-LFU]) and secondary (SF-36 Physical Component Score at latest F/U [PCS-LFU]) outcome measures between groups. Reoperation & revision rates according to the COFAS Coding System were also compared. Results: There were 349 AF and 541 TAR cases with mean F/U of 5.4 years. Age averaged 55.9 (AF) and 64.3 (TAR) years. Analysis of raw AOS and PCS scores showed no difference pre-operatively between all 8 groups; all improved from pre-operative to LFU (p<0.05). Improvement was greater for TAR than AF in all COFAS Types, leading to significantly lower (better) AOS-LFU for TAR than AF in all COFAS Types (p <0.05). Multivariate analysis (see Figure) showed increasing (worsening) AOS-LFU for AF when progressing from Type 1 to 4, leading to better outcomes for TAR compared to AF in all Types, reaching statistical significance in Types 3 and 4. Revision rates were (6.3% [AF], 7.4% [TAR], NS); Non-revision reoperation rates were (14.6% [AF], 21.3% [TAR], p=0.01). Conclusion: At mid-term, patient reported outcomes for AF worsen with increasing ESAA complexity (as defined by COFAS Type), while outcomes for TAR are not affected by ESAA complexity. Both TAR and AF have similar revision rates, though non-revision reoperation rates are significantly higher for TAR. Both TAR and AF yield similar outcomes in non-complex ESAA (Types 1 and 2). However, for Complex ESAA (Types 3 and 4), TAR leads to significantly better outcomes, suggesting TAR may be indicated over AF in the presence of significant hindfoot deformity or hindfoot arthritis in patients who are otherwise candidates for either procedure

Gender Differences in End-Stage Ankle Arthritis

Category: Ankle Arthritis Introduction/Purpose: End-stage ankle arthritis (ESAA) is a debilitating disease that does not affect all individuals equally. Gender differences have been identified in patients with end-stage hip and knee arthritis and have stimulated research to explain these findings. The present study was undertaken to examine if gender has a significant effect on pre-operative disability and post- operative outcomes in patients with ESAA. Methods: Patients undergoing ankle arthrodesis (AA) or total ankle replacement (TAR) with minimum 2-year follow-up were identified in the Canadian Orthopedic Foot and Ankle Society prospective ankle reconstruction database. Demographic data, revision data, patient satisfaction questionnaires, and outcome data using the Ankle Osteoarthritis Scale (AOS) and Short-form 36 (SF-36) health survey were collected. Results: TAR: 384 patients were included, with 198 females and 186 males. Preoperatively females had higher rates of pain and disability, demonstrated by lower SF-36 physical component scores (PCS) (31.0 vs 34.5, p < 0.001), and higher AOS pain (54.7 vs 51.1, p=0.05) and AOS disability scores (66.5 vs 59.6, p < 0.001). Postoperatively, both groups had significant improvement in PCS, AOS pain, and AOS disability scores. Females continued to demonstrate lower PCS scores (38.3 vs 41.9, p < 0.001) and higher AOS disability scores (31.0 vs 25.8, p=0.02) than males. Preoperative PCS, gender, age, and arthritis etiology all had a significant impact on postoperative PCS scores, with preoperative PCS scores having the largest impact. Gender had no significant impact on AOS pain and disability scores postoperatively. AA: Results Pending Conclusion: In patients with ESAA, females tend to have higher pre-operative levels of pain and disability compared to males, which persists post-operatively. This is consistent with the hip and knee arthroplasty literature. This finding may be due to females undergoing surgery at more advanced disease states, arthritis etiology, referral bias, or treatment bias. Both males and females have significant and similar degrees of improvement in pain and disability scores after TAR, and reoperation rates and patient satisfaction rates are similar despite the apparent disparity in outcomes

An Update on the Canadian Experience Treating End Stage Ankle Arthritis with Fusion or Replacement Surgery

Category: Ankle Arthritis Introduction/Purpose: There is much interest in the surgical treatment of end-stage ankle arthritis. Our team has previously reported comparisons between ankle fusion and replacement outcomes for 321 ankles at 5.5 years from a prospective cohort. This research extends the observational period for another six years, ending in 2013. Our primary hypothesis is that patient-reported clinical outcomes for ankle fusion and replacements would be similar at last follow up. Methods: Patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstructive Database were treated with total ankle replacement (involving Agilty, Star, Mobilty, Hintegra, or Inbone) or fusion (open or arthroscopic). Patient characteristics collected included demographics, comorbidities, smoking status and body mass index. Patient-reported outcomes (PROs) completed by patients were the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36). Pre-operative and most recent patient data, with at least four years follow-up, were analyzed. Sensitivity analyses excluded ankles that had undergone revision. A linear mixed-effects regression model compared scores between total ankle replacement and fusion groups, adjusting for patient characteristics, baseline data and surgeon. Results: The sample included 844 ankles (556 ankle replacements and 284 arthrodesis). The mean follow up period was 8.0 years (standard deviation 3.1 years), with minimum and maximum of 4 and 14 years, respectively. Patients treated with arthrodesis were younger, more likely to be diabetic and smokers, and somewhat less likely to have inflammatory arthritis. Overall, 19.4% of ankle fusion and 30.8% of ankle replacements underwent all-cause re-operation. The mean AOS total score improved from 58.6 points pre-operatively to 31.4 post-operatively (delta 27.2), and from 57.0 to 26.9 points (delta 30.1) in the ankle replacement group. Differences in the change in AOS and SF-36 scores between the arthrodesis and ankle replacement groups were minimal after adjustment for baseline characteristics and surgeon. Conclusion: Clinical outcomes of total ankle replacement and ankle arthrodesis were comparable in a diverse cohort of patients whose follow up period ranged between 4 and 14 years post-operatively

Validity of a Revision Surgery Classification System for Ankle Arthritis Surgery

Category: Ankle Arthritis Introduction/Purpose: Reoperations may be a better way of tracking adverse outcomes than complications. Repeat surgery causes cost to the system, and often indicate failure of the primary procedure resulting in the patient not achieving the expected improvement in pain and function. Understanding the cause of repeat surgery at the primary site may result in design improvements to implants or improvements to fusion techniques resulting in better outcomes in the future. Repeat operations around the primary site may also be relevant to the primary surgery. The COFAS group have designed a reoperation classification system. The purpose of this study was to outline the inter and intra observer reliability of this classification scheme. Methods: To verify the inter- and intra-observer reliability of this new coding system, six fellow ship trained practicing foot and ankle Orthopaedic surgeons were asked to classify 61 repeat surgeries. The six surgeons read the operation reports in random order, and reread the reports 2 weeks later in a different order. Reliability was determined using regression analysis and intraclass correlation coefficients (ICC) were calculated and proportions of agreement. The agreement between pairs of readings (915 for inter observer for the first and second read; 61 readings with 15 comparisons) was determined by seeing how often each observer agreed. This was repeated for the 366 ratings for intra observer readings (61 times 6). Results: The inter-observer reliability test on the first read had a mean intra-class correlation coefficient (ICC) of 0.89, range 0.80 to 0.96. For 61 cases, 45 (74%) observations that were given the same code across all six observers for the first read. The inter-observer reliability test on the second read had a mean ICC of 0.94, range .90 to to 1.0. There were 43 (72%) observations that were the same across all six observers. Of all pairs (915 in total) there was agreement in 804 pairs for the first reading (88%). For the second reading there was agreement in 801 pairs (86%). The observers agreed with themselves in the intra-observer observation 324 times out of 366 paired readings (89% agreement of pairs). Conclusion: The COFAS classification of reoperations for end stage ankle arthritis was reliable. This scheme potentially could be applied to other areas of Orthopaedic surgery and should replace the Claiden Dindo modifications that do not accurately reflect Orthopaedic outcomes. As complications are hard to define and lack consistent terminology (Mercer) reoperations and resource utilization (extra clinic visits, extra days in hospital and extra hours of surgery may be more reliable measures of the negative effects of surgery

Swelling Results in Poor Outcome After Ankle Arthritis Surgery

Category: Ankle Arthritis Introduction/Purpose: Patients often comment on swelling after foot and ankle surgery. However the relationship between swelling and outcome has not been defined. Pinsker and Daniels demonstrated that swelling was an important aspect of outcome. The purpose of this paper was to determine the relationship between swelling score and outcome after ankle fusion and replacement. A secondary purpose was to determine how this relationship changed in time, how swelling score changed before and after surgery, and determine differences in swelling score between total ankle replacement (TAR), open ankle arthrodesis (OAA) and arthroscopic ankle arthrodesis (AAA). Methods: The MODEMS outcomes package from AAOS was used, with the validated ankle osteoarthritis score (AOS) score being used to assess outcomes in the pain and disability domains. The swelling score was indexed from 1 to 5, 1 being no swelling and five being severe swelling. Outcomes were recorded pre-operatively and annually up to 2010. Statistical analysis was performed using 95% confidence intervals and correlations being determined using Pearson’s correlation and r 2 values. Results: The swelling score was correlated with AOS score preoperatively. Postoperatively patients with a swelling score of 1 had an average AOS score of 15.1 (CI 13.3 to 16.9), a swelling score of 2 had an AOS score of 23 (CI 21.7 to 24.9), 3 an AOS of 31 (CI 29.6 to 33.1), 4 an AOS of 33.6 (CI 34.9 to 38.8), and 5 an AOS of 39 (CI 35.3 to 43.0). There was therefore a difference in outcome score for all groups of swelling score (i.e. 1 scored better than 2, 2 better than 3, 3 better than 4 and 4 better than 5). Swelling scores were the same for TAR, OAA and AAA preoperatively. Postoperatively swelling scores were lower for AAA (2.1, CI 1.9 to 2.2) compared to TAA (2.5, CI 2.4 to 2.6) and OAA (2.5, CI 2.4 t0 2.6). Conclusion: Swelling has a relationship with outcome. Swelling after surgery may result in poorer outcomes. Strategies to reduce swelling such as patient education about elevation, surgical technique and the use of compression stockings may improve outcomes. Arthroscopic surgery may have better outcomes because of the reduction in postoperative swelling

Is the Canadian Orthopaedic Foot and Ankle Society Ankle Arthritis Score (COFAS AAS) Associated with the Need for Revision Surgery?

Category: Ankle Arthritis Introduction/Purpose: There has been limited evidence to support the effective use of a patient reported outcome measure (PROM) for patients that have undergone surgical treatment for end-stage ankle arthritis (ESAA). This study used longitudinally collected patient-data from a cohort of patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) ankle arthritis study to evaluate whether the post-operative COFAS Ankle Arthritis Score (COFAS AAS), a patient-reported outcome (PROs), was associated with need for revision surgery. Methods: Between 2001 and 2010, a cohort of 623 patients and 653 ankles undergoing total ankle replacement or ankle arthrodesis were enrolled in a multicenter prospective ankle reconstruction study. At pre-surgical baseline, key patient level variables were collected including demographics, body mass index, and comorbidities. The COFAS AAS, a patient-reported outcome measure was collected at baseline and annually post-surgically. Time to revision surgery was modeled using a proportional hazards model which controlled for age, sex, BMI, diabetic status, smoking status, inflammatory arthritis, and surgery on the right or left side and time varying PROs. Results: 531 ankles in 509 patients with complete pre and post-operative data were included. Seventy of the cohort underwent metal component revision procedures during the follow up time period . The remaining 461 unrevised ankles had a minimum 2 year follow up (average of 3.4 years). Baseline COFAS AAS, age, sex, side, BMI, diabetic status, smoking status, and inflammatory arthritis were not statistically associated with the need for revision surgery. However, revision surgery was found to be associated with a higher post-operative COFAS AAS, and with a longer follow-up. The hazard ratio for the COFAS AAS indicates that for every one-point increase in the score, the rate of revision surgery was one percentage point higher at each post-operative time point. Conclusion: This study demonstrated that patients who reported higher levels of post-operative functional impairment, as indicated by a higher COFAS AAS, were more likely to undergo a revision surgery. This finding is also based on duration of follow-up, with the risk of revision surgery rising with length of follow up. This study provides further evidence for the utility of the COFAS AAS in the clinical setting. Further investigation is warranted to better understand the COFAS AAS’s ability to measure clinically meaningful change in an individual patient not requiring revision surgery

Intermediate Outcomes of Hydrogel Implant for Hallux Rigidus

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus is the most common arthritic condition of the foot. Although a variety of great toe implants have been tried in an attempt to maintain toe motion, the majority have failed. In these cases, salvage to arthrodesis is more complicated and with a prolonged recovery. This prospective study assesses the intermediate efficacy and safety of a small (8/10 mm) hydrogel implant requiring minimal bone resection for moderate to severe hallux rigidus. Methods: Patients who underwent 1st MTP hemiarthroplasty with an organic polymer-based biomaterial implant (Cartiva), with at least five-year follow-up were contacted. Patients underwent a physical exam, and completed a pain visual analog scale (VAS) scale, SF-36, patient satisfaction questions, and the Foot and Ankle Ability Measure (FAAM). Results: Twenty-nine patients were available, with two lost to follow-up. The average time of follow-up was 5.3±0.5 years. The average age was 55.6±8.4, with 24(80%) females. The average VAS for pain improved from 64.6(±11.8) to 5.2(± 9.4) (p < 0.001). The average FAAM scores were: ADL subscale: 62.1(±16.4) to 95.8%(± 7.2) (p < 0.001); and Sports subscale: 40.2(±15.1) to 91.3%(±11.2) (p < 0.001); The average FAAM scores at follow-up for: Level of function during sports: 91.9%(±10.7); and Current level of function: 92.5%(±10.6). 69.2% of patients reported their level of function as normal, 26.9% nearly normal, and 3.8% abnormal function. Patients had 17.7 degrees of dorsiflexion, with a range of 12.7 to 22.7 degrees. Average peak dorsiflexion was 28.2°(±8.8). 92.3% stated they would undergo the procedure again. Conclusion: This study reports the mid-term results of an organic polymer-based biomaterial hemiarthroplasty implant for the management of hallux rigidus. Overall patients were very satisfied with the procedure. At an average of five years, patients are functioning very well, with limited pain and maintained motion of the 1st MTP joint. These results are promising as a viable alternative to fusion of the 1st MTP joint for management of moderate to severe hallux rigidus

Does Smoking Affect Outcome in Surgical Management of Ankle Arthritis? A COFAS Multicentre Study

Category: Ankle Arthritis Introduction/Purpose: Smoking has been shown to increase complication rates after ankle surgery. The aim of this study was to compare complication rates between smokers and non smokers undergoing surgery for ankle arthritis. Methods: Smokers (n=88) and non smokers (n=565) with ankle arthritis who had undergone ankle arthrodesis or ankle arthroplasty were included in the study. Multicentre, prospective data was used from the COFAS ankle arthritis database. Patients with information available on smoking habits and 2 year follow up were included Results: There was no significant difference in the overall re operation rates between smokers and non smokers. However, the amputation rate was higher in smokers (3.4%) as compared to non smokers (0.7%). AOS scores and SF 36 scores were similar in the 2 groups. A higher proportion of smokers underwent fusion (46.5%) as compared to non smokers (28.8%). Amputation rate after ankle arthrodesis was higher in smokers (4.9%) as compared to non smokers (0.6%). Conclusion: Smokers have a higher amputation rate after ankle arthrodesis or ankle arthroplasty as compared to non smokers. Information from this study can be used during counselling of surgical patient

Should 15° of Valgus Coronal-Plane Deformity Be the Upper Limit for a Total Ankle Replacement?

Category: Ankle Arthritis Introduction/Purpose: Preoperative talar valgus deformity increases the technical difficulty of total ankle replacement (TAR) and is associated with an increased failure rate. Deformity of ≥15° has been reported to be a contraindication to arthroplasty. The goal of the present study was to determine whether the clinical outcomes of TAR for treatment of end-stage ankle arthritis were comparable for patients with preoperative talar valgus deformity of ≥15° as compared to those with <15°. Methods: Fifty ankles with preoperative coronal-plane tibiotalar valgus deformity of ≥15° (“valgus” group) and 50 ankles with valgus deformity of <15° (“control” group) underwent TAR. The cohorts were similar with respect to demographics and components used. All TARs were performed by a single surgeon. The mean duration of clinical follow-up was 5.5 years (minimum two years). Preoperative and postoperative radiographic measurements of coronal-plane deformity, Ankle Osteoarthritis Scale (AOS) scores and Short Form (SF)-36 scores were prospectively recorded. All ancillary (intraoperative) and secondary procedures, complications and measurements were collected. Results: The AOS pain and disability subscale scores decreased significantly in both groups. The improvement in AOS and SF-36 scores did not differ significantly between the groups at the time of the final follow-up. The valgus group underwent more ancillary procedures during the index surgery (80% vs 26%). Tibio-talar deformity improved significantly toward a normal weight-bearing axis in the valgus group. Secondary postoperative procedures were more common in the valgus group (36%) than the controls (20%). Overall, re-operation was not associated with poorer patient outcome scores. Metal component revision surgery occurred in seven patients (three valgus and four controls). These revisions included two deep infections (2%), one in each group, which were converted to hindfoot fusions. Therefore, 94% of the valgus group retained their original components at final follow-up. Conclusion: Satisfactory midterm results were achieved in patients with valgus mal-alignment of ≥15°. The valgus cohort required more procedures during and after their TAR, as well as receiving more novel techniques to balance their TAR. Whilst longer term studies are needed, valgus coronal-plane alignment of ≥15° should not be considered an absolute contraindication to TAR if the associated deformities are addressed