Development and internal validation of a multivariable risk prediction model for severe rebound pain after foot and ankle surgery involving single-shot popliteal sciatic nerve block.

BACKGROUND: Rebound pain occurs after up to 50% of ambulatory surgeries involving regional anaesthesia. To assist with risk stratification, we developed a model to predict severe rebound pain after foot and ankle surgery involving single-shot popliteal sciatic nerve block. METHODS: After ethics approval, we performed a single-centre retrospective cohort study. Patients undergoing lower limb surgery with popliteal sciatic nerve block from January 2016 to November 2019 were included. Exclusion criteria were uncontrolled pain in the PACU, use of a perineural catheter, or loss to follow-up. We developed and internally validated a multivariable logistic regression model for severe rebound pain, defined as transition from well-controlled pain in the PACU (numerical rating scale [NRS] 3 or less) to severe pain (NRS ≥7) within 48 h. A priori predictors were age, sex, surgery type, planned admission, local anaesthetic type, dexamethasone use, and intraoperative anaesthesia type. Model performance was evaluated using area under the receiver operating characteristic curve (AUROC), Nagelkerke's R2, scaled Brier score, and calibration slope. RESULTS: The cohort included 1365 patients (mean [standard deviation] age: 50 [16] yr). The primary outcome was abstracted in 1311 (96%) patients, with severe rebound pain in 652 (50%). Internal validation revealed poor model performance, with AUROC 0.632 (95% confidence interval [CI]: 0.602-0.661; bootstrap optimisation 0.021), Nagelkerke's R2 0.063, and scaled Brier score 0.047. Calibration slope was 0.832 (95% CI: 0.623-1.041). CONCLUSIONS: We show that a multivariable risk prediction model developed using routinely collected clinical data had poor predictive performance for severe rebound pain after foot and ankle surgery. Prospective studies involving other patient-related predictors are needed. CLINICAL TRIAL REGISTRATION: NCT05018104.

Responsiveness and validity of the SF-36, Ankle Osteoarthritis Scale, AOFAS Ankle Hindfoot Score, and Foot Function Index in end stage ankle arthritis.

BACKGROUND: We examined four commonly used scores, the SF-36, the Ankle Osteoarthritis Scale (AOS), the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Score, and the Foot Function Index (FFI) to determine their responsiveness and validity. METHODS: Patients with end stage ankle arthritis were recruited into a prospective multicenter cohort study and baseline and one year outcome scores were compared. The Standardized Response Mean and Effect Size for the AOS, AOFAS, and FFI were calculated and the three region- or disease-specific scores were compared with the SF-36 to determine their criterion validity. RESULTS: All four scores showed acceptable responsiveness, and when using the validated SF-36 as the standard the three region or disease specific scores all showed similar criterion validity. CONCLUSION: All four scores are responsive and can be considered for use in this population. The objective component of the AOFAS Ankle Hindfoot Score may make it harder to perform than the other three scores which have subjective components only, and as yet its objective component has not been shown to demonstrate reliability. We recommend use of a purely subjective score such as the Ankle Osteoarthritis Scale or Foot Function Index as the region- or disease-specific score of choice in this population. As the SF-36 shows acceptable responsiveness, using it alone could also be considered.

High Pain Catastrophizing Scale Predicts Lower Patient-Reported Outcome Measures in the Foot and Ankle Patient.

BACKGROUND: Postoperative outcomes may be affected by the patient's preoperative morbidity. It is hypothesized that patient's pain catastrophization prior to foot and ankle surgery may affect their patient-reported outcomes. Methods: This study prospectively assessed a consecutive cohort of 46 patients undergoing foot and ankle reconstruction to describe the relationship between Pain Catastrophizing Scale (PCS) and patient-reported outcomes measured by 12-item Short Form Health Survey and Foot and Ankle Outcome Score (FAOS). RESULTS: The 1-year postoperative FAOS pain, activities of daily living, and quality of life scores correlated significantly with all baseline PCS subcategories. We found that the mental domain of the SF-12 had a statistically significant correlation with the rumination and helplessness PCS subcategories. CONCLUSION: This study showed a significant association between a high preoperative PCS and a worse 1-year FAOS. As such, catastrophization could be screened for and potentially treated preoperatively to improve patient-reported outcomes in elective foot and ankle surgery. LEVEL OF EVIDENCE: Therapeutic, Level III Evidence.

Sex Differences in End-Stage Ankle Arthritis and Following Total Ankle Replacement or Ankle Arthrodesis.

BACKGROUND: We investigated the influence of sex on patient-reported outcomes preoperatively and following total ankle replacement and ankle arthrodesis. METHODS: Patients who had undergone total ankle replacement or ankle arthrodesis for the treatment of end-stage ankle arthritis and who had ≥2 years of follow-up were identified from the Canadian Orthopaedic Foot and Ankle Society Prospective Ankle Reconstruction Database. Standard surgical techniques and implantation methods were followed, and STAR, Hintegra, Mobility, and Agility prostheses were used. Data were collected on patient demographics, revisions, secondary procedures, complications, Ankle Osteoarthritis Scale (AOS) scores, Short Form-36 (SF-36) scores, and expectations and satisfaction. Statistical analyses included 3-way repeated-measures analysis of variance (ANOVA) and multiple linear regression models controlling for inflammatory arthritis, age, preoperative scores, and surgery type. RESULTS: The study included 872 patients: 629 who had undergone total ankle replacement (316 men, 313 women) and 243 who had undergone ankle arthrodesis (154 men, 89 women). The mean duration of follow-up (and standard deviation) was 4.9 ± 2.4 and 4.0 ± 1.9 years for the total ankle replacement and ankle arthrodesis groups, respectively. Men were older than women (p ≤ 0.001). In both the total ankle replacement and ankle arthrodesis groups, women had higher AOS pain scores (i.e., more pain) than men preoperatively (p < 0.05). Pain was reduced significantly in both sexes postoperatively (p < 0.05), with no significant difference between sexes. In both the total ankle replacement and ankle arthrodesis groups, women had higher AOS disability scores (i.e., more disability) and lower SF-36 Physical Component Summary (PCS) scores (i.e., worse function) than men both preoperatively and postoperatively (p < 0.001). Postoperatively, AOS disability and SF-36 PCS scores improved significantly from baseline in both sexes (p < 0.001). After controlling for covariates, sex was not a significant predictor of postoperative SF-36 MCS (Mental Component Summary), AOS pain, or AOS disability scores (p > 0.05) but explained 0.5% of variance in SF-36 PCS scores (p = 0.03). Sex did not significantly influence preoperative expectations or postoperative satisfaction. When patients with inflammatory arthritis were excluded, preoperative and postoperative outcome measures, expectations, and satisfaction were similar. CONCLUSIONS: Men and women with end-stage ankle arthritis benefited from total ankle replacement and ankle arthrodesis with similar magnitudes of improvement. Small differences in pain and function between men and women undergoing total ankle replacement and ankle arthrodesis mostly disappeared when controlling for potential confounding variables. Both total ankle replacement and ankle arthrodesis remain good options for men and women with end-stage ankle arthritis. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Automated cuff occlusion pressure effect on quality of operative fields in foot and ankle surgery: a randomized prospective study.

BACKGROUND: Limb occlusion pressure, which is present when blood flow ceases, has not had a practical method described for attainment. An automated tourniquet system was modified to set tourniquet pressure based on measurement of limb occlusion pressure (LOP). In this single surgeon randomized prospective study, the effectiveness of this system was assessed on patients undergoing foot and ankle surgery. MATERIALS AND METHODS: Two hundred forty-four patients were randomized to the study group of automated pressure (n = 112) or to the control group (n = 132). The primary outcome measure was tourniquet pressure used for either group. Secondary measures included the time to set the pressure and number of patients failing LOP measurement. The tourniquet field was assessed intraoperatively and postoperatively in a blinded manner. RESULTS: The tourniquet pressure was significantly lower in the study group at 198.5 ± 20.2 mmHg compared to 259.6 ± 4.4 in the control group (p < 0.001). The time to measure the LOP was 20 ± 6 seconds. Six patients failed to be measured. The quality of the surgical field was judged to be better in the study group based on all three methods of assessment. CONCLUSION: LOP measurement was a practical way of setting tourniquet pressures for limb surgery. The automated pressure averages were lower than those routinely used by most surgeons for thigh tourniquets.

Total Ankle Arthroplasty Radiographic Alignment Comparison Between Patient-Specific Instrumentation and Standard Instrumentation.

BACKGROUND: Several benefits are published supporting patient-specific instrumentation (PSI) in total ankle arthroplasty (TAA). This study seeks to determine if TAA with PSI yields different radiographic outcomes vs standard instrumentation (SI). METHODS: Sixty-seven primary TAA patients having surgery using PSI or SI between 2013 and 2015 were retrospectively reviewed using weightbearing radiographs at 6-12 weeks postsurgery. Radiographic parameters analyzed were the medial distal tibia angle (MDTA), talar-tilt angle (TTA), anatomic sagittal distal tibia angle (aSDTA), lateral talar station (LTS), and talar component inclination angle (TCI). A comparison of the 2 groups for each radiologic parameter's distribution was performed using a nonparametric median test and Fisher exact test. Furthermore, TAAs with all radiographic measurements within acceptable limits were classified as "perfectly aligned." The rate of "perfectly aligned" TAAs between groups was compared using a Fisher exact test with a significance of .05. RESULTS: Of the 67 TAAs, 51 were done with PSI and 16 with SI. There were no differences between groups in MDTA (P = .174), TTA (P = .145), aSDTA (P = .98), LTS (P = .922), or TCI angle (P = .98). When the rate of "perfectly aligned TAA" between the 2 groups were compared, there was no significant difference (P = .35). CONCLUSION: No significant radiographic alignment differences were found between PSI and SI implants. This study showed that both techniques achieve reproducible TAA radiographic coronal and sagittal alignment for the tibial component when performed by experienced surgeons. The talar component's sagittal alignment is similar whether or not PSI was used but is noticeably different from normal anatomic alignment by design. LEVEL OF EVIDENCE: Level III, retrospective cohort study using prospectively collected data.

Inter- and intraobserver reliability of the COFAS end-stage ankle arthritis classification system.

BACKGROUND: End-stage ankle arthritis should have an appropriate classification to assist surgeons in the management of end-stage ankle arthritis. Outcomes research also requires a classification system to stratify patients appropriately. MATERIALS AND METHODS: Six fellowship trained foot and ankle surgeons met on two occasions to derive a classification system for end-stage ankle arthritis. A four-part classification system was designed. Four surgeons reviewed blinded patient profiles and radiographs on two occasions to determine the inter- and intraobserver reliability. RESULTS: Good interobserver reliability (kappa = 0.62) and intraobserver reproducibility (kappa = 0.72) was demonstrated for the classification system. CONCLUSION: The COFAS classification system appears to be a valid tool for the management and research of end-stage ankle arthritis.

Relationship of Preoperative Patient-Reported Outcome Measures (PROMs) to Postoperative Success in End-Stage Ankle Arthritis.

BACKGROUND: Ankle osteoarthritis is a significant cause of pain and disability. Despite the effectiveness of treatments, a subset of patients remains with persistent pain and functional limitations. The purpose of this study was to use preoperative patient-reported outcome measures to predict which ankle osteoarthritis patients would be most likely to experience postoperative improvements in functional outcomes. METHODS: A retrospective analysis of prospectively collected data was used to evaluate 427 patients with end-stage ankle arthritis with 5-year follow-up. Demographics, comorbidities, Ankle Osteoarthritis Scale (AOS), Ankle Arthritis Score (AAS), and the physical and mental component scores of the Short Form-36 (SF-36 Physical Components Score [PCS] and Mental Components Score [MCS]) were collected. The minimal clinically important difference (MCID) was then calculated. Receiver operating characteristic (ROC) analysis was used to choose the optimal threshold values of preoperative patient-reported outcome measure and assess the prediction performance. RESULTS: Patients who scored worst at preoperative baseline made the greatest gains in function and pain relief, and they had a high chance of achieving MCID following surgical treatment. ROC curves demonstrated that preoperative AOS, AAS, and SF-36 PCS and MCS scores were predictive of postoperative improvements in physical and mental function. Patients with preoperative AOS score above 45.7 had an 83% probability of achieving an MCID (AUC = 0.67). Similarly, patients with a preoperative AAS score above 25.7 had a 78% probability of achieving an MCID (AUC = 0.63). Patients with a preoperative SF-36 PCS score below 31 had a 62% probability of achieving an MCID (AUC = 0.64). Patients with a preoperative SF-36 MCS below 52.7 had a 47% probability of achieving an MCID (AUC = 0.89). MCIDs for AOS, AAS, SF3-36 PCS, and SF-36 MCS score changes were 12.4, 10.0, 6.43, and 8.1, respectively. CONCLUSION: Preoperative patient-reported outcomes measures could predict postoperative improvement in ankle arthritis patients. The results of this study may be used to facilitate discussion between physicians and patients regarding the expected benefit of surgery. LEVEL OF EVIDENCE: Level III, prognostic comparative study.

Does Patient-Specific Instrumentation Have a Higher Rate of Early Osteolysis Than Standard Referencing Techniques in Total Ankle Arthroplasty? A Radiographic Analysis.

Introduction: Patient-specific instrumentation (PSI) has been developed for total ankle arthroplasty (TAA), with proven benefits. One concern regarding PSI is the need for more soft tissue dissection in order to accurately position the PSI guides, which has the theoretical disadvantage of increased osteolysis. The purpose of our study is to compare the incidence and magnitude of osteolysis for the INFINITY Total Ankle System between PSI and standard referencing (SR) techniques. Methods: Sixty-seven patients who underwent primary TAA using Prophecy (PSI) or SR technique between 2013 and 2015 were reviewed in a retrospective observational study. Osteolysis was assessed on radiographs at 2 years. The incidence was calculated by binomial distribution. The number of zones compromised and the magnitude of osteolysis was calculated using the median as a summary statistic and interquartile range as dispersion statistic. Fisher exact test was used to compare both groups, then a regression model was estimated to calculate the odds ratio for osteolysis. Results: Of the 67 TAAs, 51 were in the PSI group and 16 in the SR group. In the PSI group the incidence, number of compromised zones (CZ), and magnitude was 41% (25%-59%), 1 [1-2], and 2 [2-3], respectively. In the SR group these were 36% (13%-65%), 3 [2-3], and 3 [2-4], respectively. No significant differences were found (P = .46, P = .12, P = .33). A slightly higher risk of osteolysis was found in the PSI group (odds ratio = 1.33 [0.36-4.83]) (P = .46). The majority of lesions were in 1 zone with size of 2 to 5 mm (63% for all cohort, 64% PSI, 60% SR). Two cases underwent revision for aseptic loosening, 1 in the SR group and 1 in the PSI group. Conclusion: According to our data, there is no significant difference between PSI and SR in terms of risk, incidence, size and magnitude of osteolysis in the INFINITY Total Ankle System at 2 years. Levels of Evidence: Therapeutic, Level III, Retrospective cohort study.

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.

Intraoperative Assessment of the Axial Rotational Positioning of a Modern Ankle Arthroplasty Tibial Component Using Preoperative Patient-Specific Instrumentation Guidance.

BACKGROUND: The use of patient-specific instrumentation (PSI) in modern total ankle replacement (TAR) has augmented positioning of the tibial component, eliminating the need for complex jigs. Coronal and sagittal alignment are intuitive with this design and have been studied, but axial rotation has not. The purpose of this study was to assess the relationship between the planned preoperative axial rotation as set by the PSI guide and the rotation determined intraoperatively with non-PSI instrumentation. METHODS: This was a prospective cohort study of 22 consecutive cases. The axial rotation angle between the medial gutter and the tibial implant position on the preoperative CT-scan based plan was extracted. At the time of surgery, the medial gutter alignment instrument from the non-PSI instrumentation was inserted and an intraoperative axial photograph obtained to record the angle between the medial gutter and the axial rotation guide pins set by the PSI instrumentation. The 2 measurements were compared and further statistical analysis included Pearson correlation and paired Student t test. RESULTS: The average axial rotation angle between the medial gutter and the implant on the PSI preoperative plan was 5.4 ± 2.9 degrees, whereas the intraoperative photograph from the medial gutter alignment instrument to the pin was 5.9 ±3.8 degrees. This demonstrated a Pearson correlation of R = 0.54 and a P value of .53. The average difference between the two was -0.46 (95% CI: -2.04, 1.10), meaning that components were either slightly externally rotated or that the fork was aimed internally. Based on this group, 50% (11/22) were within 2 degrees of the target and 77% (17/22) were within 4 degrees of the target. CONCLUSION: Patient-specific guides allowed for reproducible rotational tibial component implantation in modern TAR. Further work is needed to better understand the biomechanical effects of the rotational profile and consequences on survivorship. LEVEL OF EVIDENCE: Level IV, case series.

Outcomes of Total Ankle Replacement, Arthroscopic Ankle Arthrodesis, and Open Ankle Arthrodesis for Isolated Non-Deformed End-Stage Ankle Arthritis.

BACKGROUND: End-stage ankle arthritis is a disabling condition that has a similar effect on morbidity, pain, and loss of function to hip arthritis. We compared clinical outcomes of total ankle replacement (TAR) involving the HINTEGRA prosthesis (Integra LifeSciences), arthroscopic ankle arthrodesis (AAA), and open ankle arthrodesis (OAA) in patients with isolated, non-deformed end-stage ankle arthritis. METHODS: Patients ≥18 years old who underwent TAR, AAA, or OAA from 2002 to 2012 with a minimum follow-up of 2 years were retrospectively identified from the Canadian Orthopaedic Foot and Ankle Society (COFAS) Prospective Ankle Reconstruction Database. All patients had symptomatic COFAS Type-1 end-stage ankle arthritis without intra-articular or extra-articular deformity or surrounding joint arthritis. Clinical outcomes included the Ankle Osteoarthritis Scale (AOS) and Short Form-36 (SF-36). Revision was defined as removal of 1 or both metal ankle prosthesis components for TAR and as reoperation for malposition, malunion, or nonunion for AAA and OAA. RESULTS: Analysis included 238 ankles (88 TAR, 50 AAA, and 100 OAA) in 229 patients with a mean follow-up of 43.3 ± 18.5 months. The TAR group had more female patients (55%; p = 0.0318) and a higher mean age (p = 0.0005). Preoperative AOS pain, disability, and total scores were similar for all groups. SF-36 physical and mental component summary scores were similar across groups, both preoperatively and postoperatively. Improvement in AOS total score was significantly larger for TAR (34.4 ± 22.6) and AAA (38.3 ± 23.6) compared with OAA (25.8 ± 25.5; p = 0.005). Improvement in AOS disability score was also significantly larger for TAR (36.7 ± 24.3) and AAA (40.5 ± 26.4) compared with OAA (26.0 ± 26.2; p = 0.0013). However, the greater improvements did not meet the minimal clinically important difference. The TAR group underwent more reoperations than AAA and OAA groups (p < 0.0001). Revision rates were similar for all 3 groups (p = 0.262). CONCLUSIONS: AAA and OAA resulted in comparable clinical outcomes to TAR in patients with non-deformed, COFAS Type-1 end-stage ankle arthritis. The rate of component revision in patients who underwent TAR was similar to the rate of revision for patients who underwent AAA or OAA; however, TAR patients underwent a greater number of additional procedures. Overall, AAA and TAR involving the HINTEGRA prosthesis were not significantly different surgical options in terms of short-term outcomes; patients should be counseled regarding higher reoperation rates for TAR. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Neuromuscular issues in cavovarus foot.

Differential muscle weakness can cause a cavus foot deformity. Presenting complaints in the hindfoot may include ankle instability, secondary arthritis, or peroneal tendonitis. Presenting complaints in the forefoot may include stress fractures, callus formation over the lateral border of the foot, claw toes, first ray overload, and metatarsalgia. More general presenting complaints can include a drop-foot gait, decreased walking tolerance, and difficulty with shoe or orthotic fitting. To surgically correct the foot shape, soft tissue contractures need to be released, bone deformity corrected, and muscles balanced to optimize their strength and prevent recurrence of the deformity. This article reviews the diagnosis and management of the cavovarus foot secondary to longstanding muscle imbalance.

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.

Association of Ankle Arthritis Score With Need for Revision Surgery.

BACKGROUND: The Ankle Arthritis Score (AAS) is a new patient-reported outcome derived from the Ankle Osteoarthritis Scale (AOS). This study analyzed longitudinally collected data from a cohort of patients in the Canadian Orthopaedic Foot and Ankle Society (COFAS) Ankle Arthritis Study in order to evaluate whether the postoperative AAS is associated with need for revision surgery. METHODS: A multicenter, prospective, ankle-reconstruction study enrolled 653 ankles undergoing total ankle replacement (TAR) or ankle arthrodesis (AA). The AAS was given at baseline and annually during postoperative follow-up. Time to revision surgery was modeled using a proportional hazards model. The final sample included 531 ankles in 509 patients. RESULTS: Sixty-two patients underwent metal-component revision and 8 underwent arthrodesis revision during the follow-up time period. The remaining 461 unrevised ankles (300 TAR, 161 AA) had a minimum follow-up of 2 years (average of 3.4 years). Revision surgery after TAR was found to be associated with a higher postoperative AAS and a longer follow-up. The hazard ratio for the AAS indicated that for every 1-point increase in the score, the rate of revision surgery after TAR was 1 percentage point higher. CONCLUSIONS: TAR patients who reported higher levels of postoperative functional impairment, as indicated by a higher AAS, were more likely to require metal-component revision surgery. After adjustment for other patient factors, the risk of revision surgery increased with length of follow-up after TAR. This study provides further evidence for the utility of the AAS in the clinical setting. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Measuring the Operative Treatment Effect in End-Stage Ankle Arthritis: Are We Asking the Right Questions? A COFAS Multicenter Study.

BACKGROUND: Foot and ankle surgeons are increasingly relying on patient-reported outcome measures (PROMs) such as the Ankle Osteoarthritis Scale (AOS) to evaluate treatment options. The objectives of this retrospective cohort study were 2-fold: (1) to examine the AOS instrument using psychometric analysis and (2) to revise the questions on the AOS to improve the effect of questions on the score and remove redundancies. METHODS: Pre- and postoperative patient scores were obtained from AOS questionnaires in the COFAS Prospective Ankle Reconstruction Database, a cohort of patients operatively treated for end-stage ankle arthritis. A split-sample approach was used to evaluate the AOS and to propose a revised instrument. RESULTS: A total of 380 patients who had been treated with total ankle replacement or ankle arthrodesis were prospectively followed to the 2-year postoperative time point. Correlation analysis demonstrated that a number of questions on the AOS were highly correlated with other similar questions, frequently incomplete, or showed little variation between respondents. Eight of the original AOS questions were retained in the newly proposed Ankle Arthritis Score (AAS) [3 from the AOS Pain subscale and 5 from the AOS Disability subscale]. Principal components analysis (PCA) showed that these questions equally clustered into 2 domains in AAS: Basic Activity and Advanced Activity. CONCLUSIONS: The AAS is shorter and has improved psychometric properties as compared to the AOS. Further investigation is required to better characterize the clinical utility of this proposed new patient-reported outcome score. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Quality of Life in Bilateral Vs. Unilateral End-Stage Ankle Arthritis and Outcomes of Bilateral Vs. Unilateral Total Ankle Replacement.

BACKGROUND: We performed a retrospective cohort study to compare preoperative health-related quality of life (HRQoL) between patients with bilateral and those with unilateral end-stage ankle arthritis. We also compared midterm outcomes in a subgroup of patients who had undergone staged bilateral total ankle replacement (TAR) with the outcomes in the group treated with unilateral TAR. METHODS: The HRQoL before surgical treatment was compared between 53 patients with bilateral end-stage ankle arthritis identified from the Canadian Orthopaedic Foot and Ankle Society Prospective Ankle Reconstruction Database and 106 patients with unilateral arthritis selected from the same database. Short Form-36 (SF-36) and American Academy of Orthopaedic Surgeons Foot and Ankle Module (AAOS-FAM) scores were used to assess preoperative HRQoL. Midterm outcomes (implant survival, HRQoL, and reoperation and revision rates) were compared between 37 patients who had undergone staged bilateral TAR and 106 patients treated with unilateral TAR; all patients were followed for at least 2 years. RESULTS: Preoperatively, patients with unilateral disease had a higher prevalence of posttraumatic arthritis, whereas patients with bilateral disease had a higher prevalence of primary and secondary arthritis (p < 0.001). The mean preoperative SF-36 physical component summary (PCS) score in the unilateral group was higher than that in the bilateral group (p < 0.002). The mean postoperative follow-up (and standard deviation) was 5.0 ± 2.0 years in the bilateral TAR group and 4.0 ± 1.8 years in the unilateral TAR group. The patients who underwent either unilateral or staged bilateral TAR demonstrated improved SF-36 PCS scores between the preoperative and postoperative evaluations (p < 0.001). The postoperative SF-36 PCS scores were similar between the patients with unilateral TAR and those with bilateral TAR (p = 0.70). Six ankles (6%) in the unilateral cohort and 6 ankles (8%) in the bilateral cohort required revision of the metal component (p = 0.52). The mean implant survival time was 10.9 years (95% confidence interval [CI] = 10.1 to 11.7 years) in the bilateral cohort and 9.2 years (95% CI = 8.5 to 9.8 years) in the unilateral cohort (p = 0.60). CONCLUSIONS: Preoperative SF-36 scores demonstrated that bilateral end-stage ankle arthritis is a more debilitating condition than unilateral arthritis. Patients who underwent staged bilateral TAR benefited as much as patients who underwent unilateral TAR, despite having a worse preoperative health status. Metal component revision rates and implant survival were similar between the 2 groups. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Midterm Outcomes of Polyvinyl Alcohol Hydrogel Hemiarthroplasty of the First Metatarsophalangeal Joint in Advanced Hallux Rigidus.

BACKGROUND: Hallux rigidus is the most common arthritic condition of the foot. A randomized clinical trial of first metatarsophalangeal (MTP) joint hemiarthroplasty with a polyvinyl alcohol (PVA) hydrogel implant (Cartiva) demonstrated pain relief and functional outcomes equivalent to first MTP arthrodesis at 2 years postoperation, with no cases of implant fragmentation, wear, or bone loss. We prospectively determined 5-year outcomes of first MTP hemiarthroplasty with the PVA hydrogel implant. METHODS: Patients who underwent first PVA hydrogel MTP hemiarthroplasty in the previously reported trial were evaluated at 5 years postoperatively. Patients underwent physical examination and radiographic evaluation and completed a pain VAS, the Short-Form-36 (SF-36), and the Foot and Ankle Ability Measure (FAAM) sports subscale and activities of daily living (ADL) subscale. At the time of this study, 29 patients had reached 5 years' follow-up. Two were lost to follow-up, leaving 27 patients with mean age 56.1 (range, 40.1-71.9) years. Mean follow-up was 5.4 (range, 4.9-6.4) years. RESULTS: Postoperative active MTP natural joint dorsiflexion and peak MTP dorsiflexion were mean 18.2 (range, 10.0-30.0) and 29.7 (range, 10.0-45.0) degrees, respectively. Pain VAS, SF-36 PCS, FAAM ADL, and FAAM Sports scores demonstrated clinically and statistically significant improvements. Radiographically, no patient demonstrated changes in implant position, implant loosening or subsidence, or implant wear. One implant was removed because of persistent pain and converted to fusion 2 years postoperation. CONCLUSION: Five years following first MTP hemiarthroplasty with a PVA hydrogel implant, functional outcomes improved significantly, pain was reduced significantly, and the implant demonstrated excellent survivorship. LEVEL OF EVIDENCE: Level IV, prospective case series.

A Coding System for Reoperations Following Total Ankle Replacement and Ankle Arthrodesis.

BACKGROUND: Repeated surgery can be a measure of failure of the primary surgery. Future reoperations might be avoided if the cause is recognized and procedures or devices modified accordingly. Reoperations result in costs to both patient and the health care system. This paper proposes a new classification system for reoperations in end-stage ankle arthritis, and analyzes reoperation rates for ankle joint replacement and arthrodesis surgeries from a multicenter database. METHODS: A total of 213 ankle arthrodeses and 474 total ankle replacements were prospectively followed from 2002 to 2010. Reoperations were identified as part of the prospective cohort study. Operating reports were reviewed, and each reoperation was coded. To verify inter- and intraobserver reliability of this new coding system, 6 surgeons experienced in foot and ankle surgery were asked to assign a specific code to 62 blinded reoperations, on 2 separate occasions. Reliability was determined using intraclass correlation coefficients (ICCs) and proportions of agreement. RESULTS: Of a total of 687 procedures, 74.8% (514/687) required no reoperation (Code 1). By surgery type, 14.1% (30/213) of ankle arthrodesis procedures and 30.2% (143/474) of ankle replacement procedures required reoperation. The rate for reoperations surrounding the ankle joint (ie, Codes 2 and 3) was 9.9% (21/213) for ankle arthrodesis versus 5.9% for ankle replacement (28/474). Reoperation rates within the ankle joint (ie, Codes 4 to 10) were 4.7% (10/213) for ankle arthrodesis and 26.1% (124/474) for ankle replacement. Overall, 0.9% (2/213) of arthrodesis procedures required reoperation outside the initial operative site (Code 3), versus 4.6% (22/474) for total ankle replacement. The rate of reoperation due to deep infection (Code 7) was 0.9% (2/213) for arthrodesis versus 2.3% (11/474) for ankle replacement. Interobserver reliability testing produced a mean ICC of 0.89 on the first read. The mean ICC for intraobserver reliability was 0.92. For interobserver, there was 87.9% agreement (804/915) on the first read, and 87.5% agreement (801/915) on the second. For the intra observer readings, 88.5% (324/366) were in agreement. CONCLUSIONS: The new coding system presented here was reliable and may provide a more standardized, clinically useful framework for assessing reoperation rates and resource utilization than prior complication- and diagnosis-based classification systems, such as modifications of the Clavien Dindo System. Analyzing reoperations at the primary site may enable a better understanding of reasons for failure, and may therefore improve the outcomes of surgery in the future. LEVEL OF EVIDENCE: Level III, retrospective comparative cohort study based on prospectively collected data.

Minimal clinically important difference and the effect of clinical variables on the ankle osteoarthritis scale in surgically treated end-stage ankle arthritis.

BACKGROUND: There is much debate regarding the best outcome tool for use in foot and ankle surgery, specifically in patients with ankle arthritis. The Ankle Osteoarthritis Scale (AOS) is a validated, disease-specific score. The goals of this study were to investigate the clinical performance of the AOS and to determine a minimal clinically important difference (MCID) for it, using a large cohort of 238 patients undergoing surgery for end-stage ankle arthritis. METHODS: Patients treated with total ankle arthroplasty or ankle arthrodesis were prospectively followed for a minimum of two years at a single site. Data on demographics, comorbidities, AOS score, Short Form-36 results, and the relationship between expectations and satisfaction were collected at baseline (preoperatively), at six and twelve months, and then yearly thereafter. A linear regression analysis examined the variables affecting the change in AOS scores between baseline and the two-year follow-up. An MCID in the AOS change score was then determined by employing an anchor question, which asked patients to rate their relief from symptoms after surgery. RESULTS: Surgical treatment of end-stage ankle arthritis resulted in a mean improvement (and standard deviation) of 31.2 ± 22.7 points in the AOS score two years after surgery. The MCID of the AOS change score was a mean of 28.0 ± 17.9 points. The change in AOS score was significantly affected by the preoperative AOS score, smoking, back pain, and age. CONCLUSIONS: Patients undergoing arthroplasty or arthrodesis for end-stage ankle arthritis experienced a mean improvement in AOS score that was greater than the estimated MCID (31.2 versus 28.0 points).