Most Readmissions Following Ankle Open Reduction Internal Fixation are Unrelated to Surgical Site Issues

Category: Trauma Introduction/Purpose: Ankle fractures are commonly-sustained injuries, and frequently require open reduction internal fixation (ORIF). It is generally a safe and effective surgical procedure, however, as quality-based reimbursement models become increasingly affected by readmissions within thirty days, it is important to determine causes and risk factors for patients to be readmitted after discharge. Methods: Patients that underwent ORIF for ankle fractures were identified from the prospectively-collected American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database from 2013 to 2014. Baseline demographics, comorbidities, and fracture characteristics (open vs. closed, location of fracture such as lateral malleolus, medial malleolus, bimalleolar, or trimalleolar) were determined. Modified Charlson Comorbidity Index (CCI) was used as a measure of overall comorbidity burden. Rates of thirty-day adverse events and readmissions were determined, as well as the causes for readmission. Multivariable logistic regression analyses were performed to identify risk factors significantly associated with having any adverse events and being readmitted within thirty days of surgery. Results: 5,056 ankle ORIF patients were included. 167 (3.3%) were open fractures. The rate of any postoperative adverse event was 5.2%. There were 127 readmissions, with 116 (91.3%) being unplanned readmissions. Of the 116 unplanned readmissions, 49 (42.2%) were for reasons related to the surgery or surgical site, with the most common causes being deep surgical site/hardware infection (12.9%), superficial site infection (11.2%), and wound disruption (6.9%). Most readmissions were for reasons unrelated to the surgical site (51.7%), including cardiac disorders (8.6%), pulmonary disorders (7.8%), and neurologic/psychiatric disorders (6.9%). With multivariable logistic regression, the strongest risk factors for readmission were history of pulmonary disease (Odds Ratio [OR] 2.29), ASA ≥ 3 (OR 2.28), and open fracture (OR 2.04, all p < 0.05). (Figure 1) Conclusion: Postoperative readmissions following ankle fracture ORIF are important to consider in this era of quality-based hospital reimbursement models. In this cohort of 5,056 ankle ORIF cases, 2.5% of patients were readmitted within thirty days, with 51.7% of all unplanned readmissions due to causes unrelated to the surgery or surgical site. This suggests that close medical follow-up with non-orthopaedic providers may be necessary after discharge. To assist clinicians in preoperative risk stratification, predictors of readmission were history of pulmonary disease, increased ASA class, and open fracture. Higher bundled reimbursements may be justified for cases with these risk factors

Adjacent Joint Kinematics after Ankle Arthrodesis in Cadaveric Gait Simulation

Category: Ankle Arthritis Introduction/Purpose: Ankle arthrodesis is an effective treatment for decreasing pain in patients with end-stage ankle arthritis. However, all patients with an ankle arthrodesis will eventually develop adjacent joint arthritis. The etiology of adjacent joint arthritis after ankle arthrodesis is not fully understood due to the difficulty of investigating these joints in vivo. Cadaveric simulation provides a unique capability of studying intrinsic foot and ankle joint mechanics. The objective of this study was to establish the effect of ankle arthrodesis on adjacent joint kinematics using cadaveric gait simulation. We hypothesized that adjacent joint motion of the hindfoot would increase after ankle arthrodesis. Methods: Four mid-tibia cadaveric specimens were potted and secured to a static mounting fixture about a six-degree of freedom robotic platform.(Figure 1A) The nine extrinsic ankle tendons were isolated and connected to linear actuators instrumented with load cells in series. During simulations, a force plate was moved relative to the stationary specimen through an inverse tibial kinematic path. Three-dimensional ankle and hindfoot kinematics were captured using a motion capture system. After ankle arthrodesis, kinematics were recorded using the same muscle force and kinematic inputs as the intact condition to determine how the hindfoot would behave when simulating normal gait. To assess the effect of ankle arthrodesis during simulated walking on adjacent joint kinematics, pre- and post-arthrodesis kinematics of the subtalar and talonavicular joint were directly compared along the stance phase and differences were assessed using two-tailed, paired Student’s t-tests with an alpha value set at p = 0.05. Results: Subtalar and talonavicular joint plantarflexion was greater during the early phase of stance in the ankle arthrodesis condition.(Figure 1B and 1C). Talonavicular joint motion also demonstrated greater dorsiflexion during late stance following ankle arthrodesis (Figure 1C). Ankle arthrodesis had no detectable effect on axial or coronal plane motion in adjacent joints of the hindfoot. Conclusion: This study reveals that sagittal plane motion in the hindfoot is increased following ankle arthrodesis. These results provide further insight into how motion is redistributed to adjacent joints after arthrodesis during gait. Such compensatory motions may be related to changes in contact mechanics in adjacent joints which can lead to degenerative changes

Ankle and Hindfoot Kinematics After Total Ankle Arthroplasty in Cadaveric Gait Simulation

Category: Ankle Arthritis. Introduction/Purpose: Total ankle arthroplasty (TAA) is an effective treatment option for end-stage ankle arthritis. However, with reports on long-term survivorship of current implant designs still anticipated in the literature, current research has focused on assessing prosthetic function and predicting potential failure mechanisms. Cadaveric gait simulation is a valuable tool for investigating the effects of surgical techniques on foot and ankle biomechanics. The objective of this study was to assess the effect of TAA on ankle and hindfoot kinematics using cadaveric gait simulation. We hypothesized that joint motion would be altered by the change in the articular constraint associated with joint replacement. Methods: Three mid-tibia cadaveric specimens were secured to a static mounting fixture about a six-degree of freedom robotic platform. A force plate was moved relative to the stationary specimen through an inverse tibial kinematic path calculated from in vivo data. Target tendon force profiles were applied to the nine extrinsic ankle tendons by linear actuators instrumented with load cells. (Figure 1A). Ankle and hindfoot kinematics were measured from reflective markers attached to bones via surgical pins. TAA was performed using the Salto Talaris prosthesis (Bloomington, MN). After replacing the ankle joint, foot and ankle kinematics were directly measured using the same kinematic inputs and muscle force as the intact condition. To assess the effect of TAA on joint kinematics, pre- and post-TAA motions were directly compared throughout the stance phase, and differences were assessed using two-tailed, paired Student’s t-tests with an alpha value set at p = 0.05. Results: Analyses revealed that ankle joint transverse plane motion was affected by TAA, with significantly greater talar internal rotation during the middle portion of stance after joint replacement (Figure 1B). In contrast, no differences were present in ankle joint sagittal and coronal plane motion between the intact and TAA condition. Dorsiflexion was greater in the subtalar joint after TAA during early stance. Similarly, there was greater dorsiflexion in the talonavicular joint during mid-stance in the TAA condition compared to the intact condition. There were no differences observed in the coronal or axial plane in either the subtalar or talonavicular joint after TAA. Conclusion: This study revealed that the talus underwent greater internal rotation during the weight acceptance portion of gait after TAA. The ankle joint however behaved similarly with respect to sagittal and coronal plane motion throughout stance after TAA. Compensatory motion however was noted in the subtalar and talonavicular joints, with greater dorsiflexion present in both joints during stance after TAA. This abstract represents an early subset of an ongoing study; smaller yet clinically important differences may still be present, and may be detected as more specimens are completed

Outcomes of a Stepcut Lengthening Calcaneal Osteotomy (SLCO) Compared to Evans Calcaneal Osteotomy for Stage IIb Adult-Acquired Flatfoot Deformity

Category: Hindfoot Introduction/Purpose: Lateral column lengthening is a powerful procedure utilized to correct the associated abduction deformity in stage II flatfoot deformity; however, prior studies have shown complications of nonunion, graft collapse, and lateral column overload with the Evans osteotomy. The Stepcut Lengthening Calcaneal Osteotomy (SLCO) is a z-lengthening calcaneal osteotomy that can correct midfoot abduction while providing inherent stability by creating a large surface area for bony healing. The goal of our study was to compare outcomes in patients undergoing a SLCO versus an Evans osteotomy. It is our hypothesis that patients following a SLCO would have a decreased incidence of nonunion and lateral overload of the foot, and similar improvement in clinical outcome scores. Methods: All consecutive patients from 2006 to 2013 undergoing stage IIB flatfoot reconstruction from our institution’s Foot & Ankle Registry were identified and included. There were 65 Evans & 79 Stepcut patients with a minimum of two year followup. All patients undergoing flatfoot reconstruction were included regardless of associated procedures which were not significantly different between the groups (Table 1). Deformity correction was assessed using preoperative and postoperative weightbearing radiographs. Healing of the osteotomy was assessed by computed tomography (CT). Clinical outcomes were assessed by the Foot and Ankle Outcomes Score (FAOS) survey which has been validated for flatfoot. Rate of return to the OR was also assessed. Differences in continuous variables between groups were assessed with independent samples t-tests, or Mann-Whitney U tests when non-normally distributed. Differences in categorical variables between groups were assessed with chi-squared and Fisher’s exact tests. An alpha level of 0.05 was deemed statistically significant. Results: The Evans group had a 0.9 mm larger graft size (p < 0.001) than the SLCO Group (Table 2). The SLCO group had greater improvement in talonavicular coverage angle (p < 0.001) and talonavicular incongruency angle (p = 0.023) than the Evans group. The Evans group returned more often for additional surgeries (p = 0.030). While there was improvement in mean FAOS scores in both groups for all subscales, only the mean FAOS score for sports activities (p = 0.012) was statistically better in the SLCO group. Rate of nonunion was not statistically significant (p = 0.086) between groups. There was no occurrence of loss of correction or lack of healing of the main (horizontal) arm of the osteotomy site in the SLCO group. Conclusion: Patients who underwent the SLCO for stage IIb adult-acquired flatfoot deformity demonstrated excellent healing, good correction of deformity, utilized a smaller graft size for correction, and less frequently needed to have a second operation on the involved foot. Additionally when compared to the Evans osteotomy, the SLCO group had comparable improvements in FAOS scores; thus making the SLCO a reasonable alternative for lateral column lengthenin

Most Readmissions Following Ankle Fracture Surgery Are Unrelated to Surgical Site Issues

Background: Ankle fracture surgeries are generally safe and effective procedures; however, as quality-based reimbursement models are increasingly affected by postoperative readmission, we aimed to determine the causes and risk factors for readmission following ankle fracture surgery. Methods: Ankle fracture cases were identified from the prospectively collected American College of Surgeons National Surgical Quality Improvement Program from 2013 to 2014. Demographics, comorbidities, and fracture characteristics were collected. Rates of 30-day adverse events and readmissions were determined as well as the causes for readmission. Multivariable logistic regression analyses were performed to identify risk factors associated with having any adverse events and being readmitted within 30 days of surgery. Results: There were 5056 patients included; 167 (3.3%) were open fractures. The rate of any postoperative adverse event was 5.2%. There were 116 unplanned readmissions, with a readmission rate of 2.3%. Of the 116 unplanned readmissions, 49 (42.2%) were for reasons related to the surgery or surgical site, with the most common causes being deep surgical site/hardware infections (12.9%), superficial site infections (11.2%), and wound disruption (6.9%). Most readmissions were for reasons unrelated to the surgical site (51.7%), including cardiac disorders (8.6%), pulmonary disorders (7.8%), and neurological/psychiatric disorders (6.9%). The cause of readmission was unknown for 6% of readmissions. With multivariable logistic regression, the strongest risk factors for readmission were a history of pulmonary disease (odds ratio [OR], 2.29), American Society of Anesthesiologists (ASA) class ≥3 (OR, 2.28), and open fractures (OR, 2.04) (all P < .05). Conclusion: In this cohort of 5056 ankle fracture cases, 2.3% of patients were readmitted within 30 days, with at least 51.7% of all unplanned readmissions due to causes unrelated to the surgery or surgical site. Predictors of readmission included a history of pulmonary disease, higher ASA class, and open fractures. Based on these findings, we advocate close medical follow-up with nonorthopaedic providers after discharge for high-risk patients. Level of Evidence: Level III

Republication of “Most Readmissions Following Ankle Fracture Surgery Are Unrelated to Surgical Site Issues: An Analysis of 5056 Cases”

Background: Ankle fracture surgeries are generally safe and effective procedures; however, as quality-based reimbursement models are increasingly affected by postoperative readmission, we aimed to determine the causes and risk factors for readmission following ankle fracture surgery. Methods: Ankle fracture cases were identified from the prospectively collected American College of Surgeons National Surgical Quality Improvement Program from 2013 to 2014. Demographics, comorbidities, and fracture characteristics were collected. Rates of 30-day adverse events and readmissions were determined as well as the causes for readmission. Multivariable logistic regression analyses were performed to identify risk factors associated with having any adverse events and being readmitted within 30 days of surgery. Results: There were 5056 patients included; 167 (3.3%) were open fractures. The rate of any postoperative adverse event was 5.2%. There were 116 unplanned readmissions, with a readmission rate of 2.3%. Of the 116 unplanned readmissions, 49 (42.2%) were for reasons related to the surgery or surgical site, with the most common causes being deep surgical site/hardware infections (12.9%), superficial site infections (11.2%), and wound disruption (6.9%). Most readmissions were for reasons unrelated to the surgical site (51.7%), including cardiac disorders (8.6%), pulmonary disorders (7.8%), and neurological/psychiatric disorders (6.9%). The cause of readmission was unknown for 6% of readmissions. With multivariable logistic regression, the strongest risk factors for readmission were a history of pulmonary disease (odds ratio [OR], 2.29), American Society of Anesthesiologists (ASA) class ≥3 (OR, 2.28), and open fractures (OR, 2.04) (all P < .05). Conclusion: In this cohort of 5056 ankle fracture cases, 2.3% of patients were readmitted within 30 days, with at least 51.7% of all unplanned readmissions due to causes unrelated to the surgery or surgical site. Predictors of readmission included a history of pulmonary disease, higher ASA class, and open fractures. Based on these findings, we advocate close medical follow-up with nonorthopaedic providers after discharge for high-risk patients. Level of Evidence: Level III

Effect of Subtalar Arthrodesis on Gait Kinematics in the Setting of Total Ankle Arthroplasty

Category: Ankle Arthritis Introduction/Purpose: Patients undergoing total ankle arthroplasty (TAA) often have symptomatic adjacent joint arthritis and deformity. Adjunctive procedures are frequently indicated in this setting in an attempt to ensure a stable and plantigrade ankle and hindfoot postoperatively. Although subtalar arthrodesis can effectively address a degenerative hindfoot, it may also place abnormal stress on the TAA, leading to premature failure. The objective of this study was to determine the effect of subtalar arthrodesis on TAA and adjacent joint kinematics using cadaveric gait simulation. We hypothesized that differences in ankle and talonavicular joint kinematics would be observed between TAA specimens with and without subtalar arthrodesis. Methods: Three mid-tibia cadaveric specimens (all female, average age at death: 48) with neutral foot alignment and no history of lower extremity trauma or surgery were tested in a robotic gait simulator. Each tibia was secured to a static mounting fixture about a six-degree of freedom robotic platform (Figure 1A). During simulations, a force plate was moved relative to the stationary specimen through an inverse tibial kinematic path based on standardized in vivo data. Salto Talaris total ankle prostheses were implanted (Tornier, Inc., Bloomington, MN) by a foot and ankle fellowship trained orthopaedic surgeon. Gait simulation was then performed. Each specimen then underwent in situ subtalar arthrodesis via fluoroscopically guided screw placement and subsequent gait analysis. The kinematics of TAA and TAA with subtalar arthrodesis during simulated walking were then compared using two-tailed, paired Student’s t-tests with an alpha value set at p = 0.05. Results: Analyses revealed that kinematics differed between specimens with TAA and those with TAA and subtalar arthrodesis (Figure 1B). During mid-stance, less ankle plantarflexion was observed in specimens with TAA and subtalar arthrodesis, as compared to those with isolated TAA. This difference was statistically significant (p < 0.05). With regard to axial motion in the ankle, significantly less external rotation was observed in early and mid-stance in specimens with TAA + subtalar arthrodesis (p < 0.05). Talonavicular kinematics also differed between cohorts (Figure 1B). In early and late stance, significantly decreased inversion was observed in specimens with subtalar arthrodesis (p < 0.05). And in early stance, talonavicular joint adduction was significantly diminished in the TAA + subtalar arthrodesis specimens, as compared to those with isolated TAA (p < 0.05). Conclusion: Via cadaveric gait simulation, our study describes the kinematic effects of subtalar arthrodesis on TAA. When TAA is performed in the setting of subtalar arthrodesis, both ankle sagittal and axial plane motion are altered, as are coronal and axial plane motion in the talonavicular joint. Because current clinical literature remains inconclusive on this relationship, additional work must be performed to better delineate the biomechanical and clinical sequelae of TAA performed with subtalar arthrodesis