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

The Use of a Fibular Nail to Treat Ankle Fractures in Patients With Diabetes

Category: Trauma Introduction/Purpose: Patients with diabetes have difficulty healing skin and bone after ankle fractures. A paper published previously demonstrated a much higher rate of wound complications and amputation in patients with diabetes compared to those without diabetes. The purpose of this study was to analyze the outcome of patients with diabetes and ankle fractures prospectively followed using a fibular nail. The primary outcome was bone healing as assessed by CT scan at 12 weeks, and secondary outcomes were outcome scores, reoperation rates, mortality and wound complications. Methods: 10 patients with diabetes and ankle fractures (Weber b and c, isolated fibula, bi-maleolar and tri-maleolar fractures) were treated with a fibular nail for the fibular fracture, and percutaneous screw fixation for the posterior or medial maleolar fractures. Patients included were those with diabetes with an HBA1c of over 7 or other systemic complications of diabetes. Patients had to survive for 12 weeks after the procedure for inclusion. Excluded were fractures outside the ankle, concomitant injuries, patients unable to follow the study protocol and those with open injuries. The CT scans were assessed on both the Sagittal and Coronal views for bone healing at the fracture site. Each slice was measured for the percent of bone bridging. Results: One patient was excluded because of mortality before the 12 week visit. A second patient survived the 12 week follow up and died before 24 weeks. Successful bone bridging was seen in all patients by 12 weeks. The bone bridging was estimated to be 70 +/- 16% (SD) on the sagittal view and 75 +/- 10% on the coronal view at 12 weeks and was on the 82% sagittal view and 80% on the coronal view at 24 weeks. No hardware failure was seen. No fracture failed to unite. There were no mal-unions or non-unions either clinically or radiographically. There was one proximal locking screw wound treated with debridement and antibiotics with successful outcome. This patient developed a charcot arthropathy and underwent ankle fusion. Conclusion: This prospective case series demonstrates that the fibular nail can generate successful bone healing and excellent alignment after ankle fractures in patients with diabetes. A further comparative study with plate fixation is merited

Predicting Failure in Total Ankle Arthroplasty. A COFAS study

Category: Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty (TAA) and ankle arthrodesis (AA) are standard treatment modalities for end-stage ankle osteoarthritis. The total ankle arthroplasty (TAA) anatomical alignment is critical for the longevity of total ankle components. Coronal and sagittal malalignment results in altered joint mechanics and reactive forces that result in implant failure. Also, to our knowledge, tibial component sizing in the sagittal plane has been addressed in knee arthroplasty literature, but not in ankle arthroplasty literature. Based on these parameters, we developed a novel radiographic predictive score for failure in TAA (RPSFT). Methods: A retrospective review performed on the COFAS database, selecting for all total ankle replacements done at a single institution between September 2004 and June 2015. Those with complete series of anteroposterior and lateral standing ankle radiographs, both preoperative and postoperative and a minimum of 1 year of follow-up, were included. We performed a multivariate logistic regression, using the medial distal tibial component angle, lateral talar station, talar tilt angle, and the absence of posterior under= or overhang of the tibial component in the first post-operative radiographs. These parameters were used to develop a RPSFT. Binomial regression was used to determine each variable’s weight in the RPSFT and assigned a corresponding score value. A univariate logistic regression was estimated, using the RPSFT as the independent variable and mechanical failure as the dependent variable. Then a Receiver-Operating Characteristic curve was constructed and the probability of failure for each possible score was estimated. Results: Of a total of 296 TAAs, 146 were included, and 8 TAAs required revision (5%). TAA revision was defined as a reoperation to remove one or both metal components, or amputation. According to our predictive score, if all the parameters are within established normal ranges (17 points) the TAA failure probability (TFP) is 2% [0-0.1] p<0.01. If none of them are obtained (0 points) the TFP rise to 42% p<0.01 (see attached table). Time to TAA failure averaged 4.4 years and ranged from 1.4 to 9.6 years. Conclusion: Our model suggests that a coronal and sagittal alignment and absence of tibial implant under/overhang are of vital importance to prevent TAA failure. To our knowledge, this is the first study that presents a predictive score for failure in TAA using postoperative ALSAR. Further data analyses are ongoing and may expand our predictive model to include other radiographic parameters

Resource Utilization After Ankle Arthritis Surgery

Category: Ankle Arthritis Introduction/Purpose: As an alternative to ankle replacement, ankle arthrodesis remains a mainstay in the treatment of end- stage arthritis. Arthroscopic techniques for ankle arthrodesis have more recently been developed, although there has been limited research exploring the cost of arthroscopic (AAA) versus open ankle arthrodesis (OAA), and comparing ankle fusions to replacement (TAA). We hypothesize that resource use after AAA will be lower than that after OAA, and both will be lower than TAA. Methods: We performed a retrospective review of a prospectively collected database. The COFAS database was used to identify patients with >2 years of follow up who have undergone AAA, OAA or Hintegra TAA at St Paul’s Hospital between 2003-2010. Ninety patients with TAA, 52 with AAA and 56 with OAA met our inclusion criteria. The following data were documented: patient demographics (age, gender, presence of diabetes, inflammatory arthritis or any smoking history), factors related to the index surgery (type of surgery, OR time, length of stay) and factors relating to the post-operative course (number of unplanned post-operative clinic visits, OR time for re-operations, length of stay for additional hospital admissions). For all significant comparisons, p < 0.05. Results: AAA required less primary surgery OR time and shorter primary hospital stay vs. TAA and OAA. Patients required more additional follow-up visits for TAA and OAA vs. AAA. TAA required more additional days in hospital compared to OAA or AAA. For each primary TAA, on average an additional seven clinic visits, 60 minutes of revision surgery, three days in hospital were required on top of the cost assigned for the primary arthroplasty. For each primary AAA, an additional four clinic visits, 23 minutes of revision surgery and one day in hospital were required. For each primary OAA, an average additional five clinic visits, three minutes of revision OR time, and 0.2 days of additional hospital stay were required. Conclusion: Using several measures of resource use, we find that arthroscopic ankle fusions compare favourably to both ankle replacements and open ankle fusions. We also show that resource utilization measurements can be a useful surrogate for complications, and that resource utilization can demonstrate the practical implications of complications for patients, surgeons and health care providers or payers

A Prospective Cohort-Study on the Return to Work and Function Two Years After Surgical Treatment of Tibiotalar Arthritis

Category: Ankle Arthritis Introduction/Purpose: Ankle arthritis is a debilitating condition. People who are affected by end stage ankle arthritis are as symptomatic as arthritis in other main articulations of the lower extremity, and often present with concurrent medical conditions and comorbidities. Once these patients cannot perform their job due to disabling arthritic ankle, they leave the workplace and require financial aid. The purpose of this study was to determine the work status before and after surgery for end stage ankle arthritis in the working age population. We hypothesized that middle-age patients at the time of surgery [55 years-old and younger] were able to go back to work within 2 years of their index ankle procedure and not depend on social / subsidized programs. Methods: Since 2001, patients treated for end-stage ankle arthritis in three Canadian centers were offered to partake in the Canadian Orthopedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstruction Database. The modalities of treatment included total ankle replacement and ankle arthrodesis (open and arthroscopic). A survey was given to patients at various points of the study, which included the MODEMS questionnaire from AAOS and SF-36. This study used the pre-operative survey, including the along with the same survey filled by patients 2 years post-operatively. Degenerative osteoarthritis, post-traumatic osteoarthritis and inflammatory arthritis requiring surgical intervention was the main inclusion criteria. Patients over 55 years- old at the time of surgery were excluded. Results: This group had 211 patients of age 47±8 and was balanced as far as sex (113 M) and side (102 L). The employment rate for this group should be 79.2 per Statistics Canada. The employment rate prior to surgery was 56% and increased to 63% two years later. The additional 7% were on leave of absence or disability prior to surgery. At the two-year follow-up, 92 patients reported less pain with work, 88 patients reported that the surgery met their expectations and 78 reported minimal interference with their work. With regards to WCB, Disability and Social Security, 115 (56%) were never on any of the above, 41 (20%) were no longer on any two years post-operative and 9 (4%) entered at least one program. Conclusion: The two-year follow-up after tibiotalar arthrodesis or arthroplasty in patients younger than 55 years-old shows that more people are able to get back to work than go off work. It also shows that more people are able to get off subsidized programs and that there is an overall satisfaction with regards to pain, inference with work and expectation. After surgery, this patient population still has a lower employment rate than the normal population. More research would be needed to better outline strategies that could reduce the disability within this group and maintain them in the workforce

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

Long-Term Outcomes of Infinity Total Ankle Arthroplasty Compared to Ankle Arthrodesis

Category: Ankle Arthritis; Ankle Introduction/Purpose: End-stage ankle arthritis causes severe pain and disability. The most common treatment has been ankle arthrodesis (AA) with proven long-term results. However, total ankle arthroplasty (TAA) has become a viable option to preserve ankle joint motion, relieve pain and shield adjacent joints. And with the evolution of TAA prostheses over the past 2 decades, the use of TAA has been steadily increasing. Nevertheless, long term outcome data on the latest generation of TAA prostheses is scarce. The primary purpose of this study is to evaluate long-term PROMs after Infinity™ TAA and to compare the outcome to a patient cohort of ankle arthrodesis (AA) performed during the same time period. Methods: Patients with end-stage ankle arthritis who received surgical treatment with a primary Infinity TAA or AA performed between 2013-2015 were included in this study. All surgeries were performed by four fellowship trained foot and ankle surgeons. Patient reported outcomes (PROMs) comprising the AOS and SF-36 PCS score were prospectively collected for patients who were willing to enroll into the Canadian Orthopaedic Foot and Ankle Society (COFAS) database. PROM data was compared between the TAA and AA patient cohorts. Implant survivorship as well as revision and reoperation rates were also analyzed. Results: 33 patients/ankles underwent primary Infinity™ TAA and 59 patients/ankles underwent AA. Of these, 25 TAA and 46 AA were enrolled in the prospective database, 20 and 46 had PROMs available for follow-up, respectively. Mean TAA PROM follow- up was 6.8 years (3-9) and for AA 6.4 years (2-9). Mean TAA age at surgery was 67 years (54-85) and 58 years for AA (27-84). TAA total AOS score pre-operatively was 52.9, which improved significantly to 23.9. SF-36 PCS scores improved from 33.1 to 43.3. Pre- and post-operative PROMs were similar to the AA cohort. At clinical follow up of 8-10 years, TAA implant survival was 97% with one metal component exchange. Two TAA patients had two reoperations each. In the AA cohort, the reoperation rate was 10.8%. Conclusion: This is the first report on patient reported outcomes and implant survival at 8 or more years after primary Infinity™ TAA. PROMs remain significantly improved at long term follow-up and are comparable to a cohort of long-term AA patients. Revision rates were low with a single component revision in 33 patients resulting in an implant survivorship of 97%. Long-term outcome of the Infinity™ total ankle arthroplasty is promising

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

Does Patient-specific Instrumentation Yield Better Component Position than Standard Instrumentation in Total Ankle Arthroplasty?

Category: Ankle Arthritis Introduction/Purpose: The unique anatomy and biomechanics of the ankle joint have made total ankle arthroplasty (TAA) challenging over the past few decades. Final implant position and successful soft tissue balancing are key components to the longevity of total ankle implants. Preoperative computer navigation, templating, and patient-specific instrumentation (PSI) have shown promising results in total ankle replacement with accurate and reproducible radiographic outcomes. Recent data has also suggested that even experienced surgeons benefit from the improved time efficiency of PSI. The purpose of this study is to determine if radiographic outcomes differ between patients undergoing TAA with PSI and those who undergo TAA with standard instrumentation (SI). Methods: The first 67 consecutive patients who underwent primary Infinity total ankle arthroplasty (TAA) at 2 North American sites between 2013 and 2015 were reviewed in a prospective observational study. All TAA’s were performed by one of four fellowship-trained foot and ankle surgeons. Demographic, radiographic, and functional outcome data was collected preoperatively, at 6-12 months postoperatively, and annually thereafter. The radiographic variables measured were the medial distal tibial angle (MDTA), talar tilt angle (TTA), lateral talar station (LTS), sagittal distal tibial articular angle (sDTAA), and the gamma angle. Acceptable intervals for each parameter were selected and TAAs were then categorized as being “correctly aligned” or “not correctly aligned” for all the parameters described. The rate of “correctly aligned” TAA’s was compared between cases with PSI and those with SI. Fisher’s exact test was used to analyze difference by groups. A significance of 5% was used. Results: Of a total of 67 TAAs included, 51 were in the PSI group and 16 in the SI group. No significant statistically differences were found between PSI and NPSI regarding MDTA (p=0.174), LTS (p=0.922), sDTAA (p=0.986), gamma angle (p=0.252) and TTA (p=0.145). We did not find a significant statistical difference in the rate of “correctly aligned TAR” when we compared both groups (p=0.35). Conclusion: This study suggests that both PSI and SI provide accurate and reproducible TAA radiographic alignment when performed by experienced surgeons. In view of previously published data demonstrating high levels of reproducibility for PSI in TAA, these data also suggest that PSI may offer a means for less experienced surgeons to achieve radiographic results similar to those achieved by experienced surgeons. It also suggests that experienced surgeons may not need to use PSI to achieve satisfactory implant alignment, though improved time efficiency with PSI, as demonstrated in other studies, may still be of benefit for experienced surgeons