Fusion of the subtalar joint for post-traumatic arthrosis: a study of functional outcomes and non-unions

Parallel versus Angulated Screw Configuration in Subtalar Arthrodesis for Posttraumatic Arthritis

Background

To compare radiographic union and clinical outcomes between parallel and angulated screw configurations (SCs) for patients undergoing subtalar arthrodesis due to posttraumatic subtalar arthritis (PSA) after displaced intra-articular calcaneal fractures.

Methods

This study retrospectively reviewed 140 consecutive PSA cases from March 2011 to November 2021 (parallel SC: group 1, n = 80; angulated SC: group 2, n = 60). Radiographic union, Foot and Ankle Outcome Score (FAOS), and visual analog scale (VAS) scores were among the outcome assessments. Six months after surgery, nonunion was confirmed based on plain radiographs, clinical evaluation, and computed tomography.

Results

Groups 1 and 2 included 14 (17.5%) and 3 (5.0%) nonunion cases, respectively (p = 0.035). There was no significant difference in preoperative FAOS and VAS scores between the groups. However, group 2 had significantly better clinical outcomes in 2 of the 5 FAOS domains (sports and quality of life), as well as VAS scores at 3 and 6 months postoperatively and at the final follow-up (p < 0.05).

Conclusions

Using the angulated SC for PSA had a lower nonunion rate and superior clinical outcomes than the parallel SC. Obtaining better radiological and clinical outcomes when using the angulated SC, rather than the parallel SC, would be advantageous.

Optimizing Subtalar Arthrodesis: A Human Cadaveric Evaluation of a Novel Partially-Threaded Screw Combination in the Delta Configuration

Background and Objectives: Despite the established role of subtalar joint arthrodesis (SJA) for treatment of subtalar osteoarthritis, achieving bone union remains challenging, with up to 46% non-union rates. Adequate compression and stable fixation are crucial for successful outcomes, with internal screw fixation being the gold standard for SJA. The delta configuration, featuring highly divergent screws, offers stability, however, it can result in hardware irritation in 20-30% of patients. Solutions to solve this complication include cannulated compression screw (CCS) countersinking or cannulated compression headless screw (CCHS) application. The aim of this biomechanical study was to investigate the stability of a delta configuration for SJA utilizing either a combination of a posterior CCHS and an anterior CCS or a standard two-CCS combination. Materials and Methods: Twelve paired human cadaveric lower legs were assigned pairwise to two groups for SJA using either two CCSs (Group 1) or one posterior CCHS and one anterior CCS (Group 2). All specimens were tested under progressively increasing cyclic loading to failure, with monitoring of the talocalcaneal movements via motion tracking. Results: Initial stiffness did not differ significantly between the groups, p = 0.949. Talocalcaneal movements in terms of varus-valgus deformation and internal-external rotation were significantly bigger in Group 1 versus Group 2, p ≤ 0.026. Number of cycles until reaching 5° varus-valgus deformation was significantly higher in Group 2 versus Group 1, p = 0.029. Conclusions: A delta-configuration SJA utilizing a posterior CCHS and an anterior CCS is biomechanically superior versus a standard configuration with two CCSs. Clinically, the use of a posterior CCHS could prevent protrusion of the hardware in the heel, while an anterior CCS could facilitate less surgical time and thus less complication rates.

The value of bone SPECT/CT in evaluation of foot and ankle arthrodesis and adjacent joint secondary osteoarthritis

OBJECTIVE

To evaluate the value of SPECT/CT (single photon emission computed tomography/computed tomography) in foot and ankle arthrodesis and development of secondary osteoarthritis in the adjacent joints.

MATERIALS AND METHODS

SPECT/CT of 140 joints in the foot and ankle (34 upper ankle (UA), 28 lower ankle (LA), 27 talonavicular (TN), 12 calcaneo-cuboidal (CC), and 39 other smaller joints after arthrodesis in 72 patients were evaluated retrospectively regarding fusion grade in CT (0 = no fusion, 1 =  < 50% fusion, 2 =  > 50% fusion, 3 = complete fusion) and radiotracer uptake (0 = no uptake, 1 = mild uptake, 2 = moderate uptake, 3 = high uptake) on SPECT/CT. Severity of osteoarthritis (1 = mild, 2 = moderate, 3 = severe) and radiotracer uptake grade in adjacent joints was also assessed. In 54 patients, clinical information about interventions in the follow-up was available.

RESULTS

According to the SPECT/CT, arthrodesis was successful (grade 2 or 3 CT fusion and grade 0 or 1 uptake) in 73% (25/34) of UA joints, 71% (20/28) of LA joints, 67% (18/27) TN, 100% (12/12) CC joints, and 62% (24/39) of other smaller joints. In 12 joints, there were discrepant findings in SPECT/CT (fusion grade 2 and uptake grade 2 or 3 (n = 9); or, fusion grade 0 or 1 and uptake grade 1 (n = 3)). The fusion rate 6-12 months after arthrodesis was 42% (14/33), 59% (20/34) after 13-24 months, and 89% (65/73) after more than 24 months, respectively. Average radiotracer uptake in arthrodesis decreased with age: 6-12 months: 1.60, 12-24 months: 1.32,  > 24 months: 0.38. There was a significant negative correlation between radiotracer uptake grade and CT fusion grade. Osteoarthritis was observed in 131 adjacent joints. During the post scan follow-up, additional arthrodeses were performed in 33 joints, of which 11 joints were re-arthrodesis and 22 were new arthrodeses in osteoarthritic adjacent joints. All these 11 joints with failed arthrodesis had grade 0 of CT fusion and grade 2 or 3 of radiotracer uptake. All 22 adjacent joints with osteoarthritis, which subsequently underwent arthrodesis, had grade 2 or 3 radiotracer uptake, and the primary arthrodesis joints were healed and fused in all these cases.

CONCLUSION

Bone SPECT/CT is a valuable hybrid imaging tool in the evaluation of foot and ankle arthrodesis and gives additional useful information about the development of secondary osteoarthritis in the adjacent joints with higher value for the assessment of secondary osteoarthritis. A practical four-type classification ('Lucerne Criteria') combining metabolic and morphologic SPECT/CT information for evaluation of arthrodesis joints has been proposed.

Establishing Baseline Radiological Metrics of the Talus and Calcaneus: A Retrospective Analysis of Computed Tomography Imaging in an Irish Cohort

Introduction The subtalar joint anatomy is complex and heterogeneity in its morphology creates unique challenges for foot and ankle surgeons. Anatomical metrics used for prosthesis design are well established. However, there is a paucity of literature quantifying foot and ankle measurement techniques and metrics used for prosthesis design. The aim of this study was to document reproducible measurement techniques and quantify talar and calcaneal metrics in a sample of Irish patients on computed tomography imaging to aid in the design of a novel hindfoot plate. Methods A retrospective analysis of consecutive foot and ankle computed tomography images performed at our institution was undertaken. Five measurements were performed on each foot and ankle image. Statistical analysis was performed to identify if a correlation existed between measurements. Results Sixty-four CTs met the inclusion criteria. Talar body height 27.1 mm (SD 2.17 mm), talar neck width 32.7 mm (3.16 mm), talar head height 25.41 (SD 2.16 mm), lateral process to posterior talus 23.6 (2.64 mm), calcaneal height 43.8 mm (SD 3.9 mm). A positive correlation was identified between all measurements. Conclusion This study identified that there was a low degree of heterogeneity in talar and calcaneal measurements in an Irish cohort. Furthermore, the metrics used in this study will provide valuable information for the preliminary design of a novel hindfoot plate.

Effect of Arthrodesis Device Type and Trajectory on Subtalar Joint Compression

The use of subtalar arthrodesis procedures has been widely implemented to relieve hindfoot issues after failure of conservative treatments; however, fusion failures persist in some patients with certain risk factors. Currently, surgeons utilize cannulated screws in these arthrodesis procedures to immobilize the subtalar joint. Recent clinical studies have demonstrated improved fusion outcomes in at-risk patients using sustained dynamic compression devices in the tibiotalocalcaneal complex. These devices utilize pseudoelastic nitinol which enables sustained dynamic compression when faced with postoperative bone resorption, joint settling, and bone relaxation. While the clinical success of these devices has been established in the tibiotalocalcaneal complex, the ability of sustained dynamic compression devices to apply joint compression in the subtalar joint has not been quantified. As such, the goals of this study were to (1) compare the ability of static compression devices and sustained dynamic compression devices to apply joint compression and (2) assess the impact of device trajectory on joint compression. A custom mechanical testing fixture was utilized to test the compression applied across the subtalar joint by one sustained dynamic compression device (in anterior and posterior trajectories) as compared to 2 cannulated screws (in both parallel and diverging trajectories). Testing revealed the sustained dynamic compression devices generated 53% greater compression as compared to the static compression devices, despite single versus dual device usage, respectively. Additionally, both types of devices applied joint compression forces in an insertion trajectory-independent manner. These data illustrate the ability of a single SDC device to maintain significantly improved joint compressive forces as compared to 2 static cannulated screws, regardless of insertion trajectory. These SDC devices may be of particular interest for at-risk patients or in revision cases.

Factors influencing successful bone union of isolated subtalar arthrodesis for posttraumatic subtalar arthritis: a multicenter case series

BACKGROUND

The purpose of this study was to find the factors influencing successful bone union for isolated subtalar arthrodesis in posttraumatic subtalar arthritis following calcaneal fracture.

MATERIAL AND METHODS

We retrospectively analyzed the rate of successful bone union of 119 cases of isolated subtalar arthrodesis for posttraumatic subtalar arthritis performed at five university hospitals between January 2010 and December 2019. Multivariate logistic regression analysis was used to find the factors associated with successful bone union. Successful bone union was defined as resolution of hindfoot pain with the presence of osseous trabecular bridging involving more than 50% of the posterior facet within 6 months postoperatively.

RESULTS

There were 77 (64.7%) cases of successful bone union, 11 (9.2%) cases of delayed union, 8 (6.7%) cases of questionable union, and 23 (19.3%) cases of nonunion. Use of fully threaded screws was 5.90 times [odds ratio (OR) = 5.90, 95% confidence interval (CI) = 1.42-24.49, p = 0.02] more likely to achieve successful bone union compared to the use of partially threaded screws. Use of two parallel screws or the two divergent screws were 3.71 times (OR = 3.71, 95% CI = 1.05-13.14, p = 0.04) and 4.65 times (OR = 4.65, 95% CI = 1.23-17.53, p = 0.02) more likely to achieve successful bone union compared to the use of a single screw. Use of cancellous autograft or structural autograft was 4.72 times (OR = 4.72, 95% CI = 1.17-19.06, p = 0.03) and 7.12 times (OR = 7.12, 95% CI = 1.46-34.68, p = 0.02) more likely to achieve successful bone union compared to no graft use.

CONCLUSION

Use of fully threaded screws, autograft, and two screws compared to a single screw were the factors associated with successful bone union within six postoperative months after subtalar arthrodesis for the posttraumatic arthritis.

Factors associated with nonunion of the posttraumatic subtalar arthrodesis after displaced intra-articular calcaneal fractures

BACKGROUND

This study investigated the incidence of and risk factors for nonunion in patients with posttraumatic subtalar arthrodesis (SA).

METHODS

We retrospectively reviewed 165 posttraumatic SA cases. Nonunion was diagnosed at 6 months after surgery based on the findings of clinical evaluations, plain radiographs, and CT scans. Patient-specific factors and surgeon-specific factors were evaluated as potential risk factors.

RESULTS

The overall nonunion rate was 13.3 % (22 of 165 cases). In the final multivariate logistic regression analysis, smoking (odds ratio [OR] = 3.64; 95 % confidence interval [CI] = 1.23-10.75), parallel screw configuration (OR = 5.70; 95 % CI = 1.62-20.06), and freeze dried iliac crest (OR = 9.16; 95 % CI = 2.28-36.79) were demonstrated as risk factors for nonunion of posttraumatic SA.

CONCLUSION

Patients with a history of smoking, parallel screw configuration fixation, and those who received freeze dried iliac crest as an interpositional graft, had a significantly higher rate of nonunion.

Y-shape osteotomy combined with subtalar arthrodesis for calcaneus malunion: a retrospective study

BACKGROUND

This retrospective study aimed to introduce a novel method for simultaneous Y-shape osteotomy combined with subtalar arthrodesis for calcaneus malunion and to evaluate the feasibility of this method.

METHODS

We retrospectively analysed the clinical and imaging data of 11 patients with calcaneus malunion treated using Y-shape osteotomy and subtalar arthrodesis who were admitted to our hospital from June 2018 to October 2020. The patients included 9 males and 2 females aged from 24 to 69 years old, with an average age of 42.18 years. The clinical and radiological results were assessed with the Visual Analogue Scale (VAS) pain score and American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score. In addition, functional recovery and general quality of life were evaluated using the 12-Item Short-Form Survey (SF-12).

RESULTS

All radiological parameters were significantly improved at the last follow-up, with increases of 14.37°, 9.18°, and 4.51 mm in the Böhler's angle, calcaneal pitch angle, and talocalcaneal height, respectively, and decreases of 6.39 mm and 6.18° in the calcaneal width and Hindfoot alignment angle (p < 0.05). The mean AOFAS and VAS scores at the last follow-up improved compared with those preoperatively, from 34.18 ± 9.53 to 84.18 ± 11.59 and from 6.90 ± 1.22 to 1.90 ± 1.13, respectively (p < 0.05). The SF-12 physical and mental health scores were 49.65 ± 6.84 and 52.68 ± 7.88, respectively. Furthermore, the early postoperative complications included skin necrosis in one and sural neuralgia in one patient, and the late postoperative complication included ankle pain in one patient. No other complications, such as implant discomforts, malunion, nonunion and re-fracture, were presented.

CONCLUSION

These results indicate that Y-shape osteotomy combined with subtalar arthrodesis is an effective new method for the treatment of calcaneal malunion. Advantages include improvement of the anatomic shape of the calcaneus and union rates for subtalar arthrodesis.

General Considerations About Foot and Ankle Arthrodesis. Any Way to Improve Our Results?

Nonunion and adjacent joint osteoarthritis (OA) are known complications after a fusion procedure, and foot and ankle surgeons are commonly exposed to such disabling complications. Determining who is at risk of developing nonunion is essential to reducing nonunion rates and improving patient outcomes. Several evidenced-based modifiable risk factors related to adverse outcomes after foot and ankle arthrodesis have been identified. Patient-related risk factors that can be improved before surgery include smoking cessation, good diabetic control (HbAc1 <7%) and vitamin D supplementation. Intraoperatively, using less invasive techniques, avoiding joint preparation with power tools, using bone grafts or orthobiologics in more complex cases, high-risk patients, nonunion revision surgeries, and filling in bone voids at the arthrodesis site should be considered. Postoperatively, pain management with NSAIDs should be limited to a short period (<2 weeks) and avoided in high-risk patients. Furthermore, early postoperative weight-bearing has shown to be beneficial, and it does not seem to increase postoperative complications. The incidence of surrounding joint OA after foot and ankle fusion seems to increase progressively with time. Owing to its progression and high probability of being symptomatic, patients must be informed consequently, as they may require additional joint fusions, resulting in further loss of ankle/foot motion. In patients with symptomatic adjacent joint OA and unsatisfactory results after an ankle arthrodesis, conversion to total ankle arthroplasty (TAA) has become a potential option in managing these complex and challenging situations.

Subtalar Arthrodesis Union Rates With and Without Adjacent Ankle Arthrodesis

BACKGROUND

Subtalar arthrodesis is the surgical procedure commonly performed to treat subtalar arthritis. Subtalar arthrodesis may have a higher nonunion rate if there is a preexisting adjacent joint arthrodesis. The aim of this retrospective cohort study was to compare the subtalar arthrodesis union rate of patients with native tibiotalar joints to that of patients with prior tibiotalar arthrodesis. The secondary aim was to assess risk factors for nonunion.

METHODS

A retrospective cohort study of consecutive patients that underwent a subtalar arthrodesis in a single center between 2010 and 2020. The primary outcome of union was determined based on bridging callus on radiographs and clinical symptoms. If there was uncertainty, then a nonweightbearing CT was acquired. Chi-squared test and Mann-Whitney tests compared differences in demographics and risk factors for nonunion between groups. A logistical regression model was performed to determine risk factors for nonunion.

RESULTS

Eighteen patients had an adjacent ankle arthrodesis and 53 patients did not. The successful subtalar arthrodesis union rate in those with a preexisting ankle joint arthrodesis (44.4%) was approximately half that in those without an ankle joint arthrodesis (86.8%) (P < .001). On multivariate logistic regression, an adjacent ankle arthrodesis was the only significant risk factor for nonunion. The odds ratio of nonunion of the subtalar joint with an adjacent ankle arthrodesis present was 4.90 (95% CI 1.02-23.56) compared to a subtalar arthrodesis with a native ankle joint. In addition, 9.4% of patients without an ankle arthrodesis underwent a revision subtalar arthrodesis compared with 44.4% of those with an adjacent ankle arthrodesis (P = .001).

CONCLUSION

In our study, we found that patients undergoing a subtalar arthrodesis with an adjacent ankle arthrodesis have a significantly increased risk of nonunion compared with those undergoing a subtalar arthrodesis with a native ankle. Patients with a previously fused ankle need counseling about the high risk of nonunion and potential additional surgery.

Persistent Pain After Hindfoot Fusion

One of the most challenging problems facing orthopedic surgeons is persistent pain after surgery and certainly is just as frustrating following hindfoot fusion. The hindfoot joints consist of the subtalar, talonavicular, and calcaneocuboid (CC) joints. These joints are commonly fused for degenerative changes, deformity correction, inflammatory or neuropathic arthropathy, tarsal coalition, or primarily after trauma. Goals of hindfoot fusion are a painless plantigrade foot capable of fitting in shoes without orthotics or a brace. Many believe that deformity correction is achievable without inclusion of the CC joint. Managing patient expectations is important when counseling a patient especially regarding potential complications.

Outcomes of Posterior Arthroscopic Subtalar Arthrodesis for Medial Facet Talocalcaneal Coalition

BACKGROUND

Medial facet talocalcaneal coalition can be a painful condition. This study aimed to determine clinical and radiographic outcomes of posterior arthroscopic subtalar arthrodesis (PASTA) for adult patients presenting with symptomatic medial facet talocalcaneal coalition and normal hindfoot alignment, with a minimal follow-up of 18 months.

METHODS

Between June 2017 and July 2019, this procedure was performed on 8 feet (8 patients; mean age, 55 [42-70] years; mean BMI, 29.8 [24.4-45.0] kg/m²). Clinical assessment was performed using Visual Analog Scale for Pain (VAS-P), Foot and Ankle Outcome Score (FAOS) and the 36-Item Short-Form Health Survey (SF-36). Patient satisfaction was assessed at the last available follow-up as "very satisfied", "satisfied" or "unsatisfied". Radiographic analysis was performed using plain radiography, computed tomography (CT) scan and magnetic resonance imaging (MRI). The primary outcome was to determine both clinical and radiographic outcomes.

RESULTS

The mean follow-up was 25.1 (18.2-34.2) months. The authors found statistically significant improvement on all clinical scores (VASP-P, FAOS and SF-36). They registered 6 "very satisfied" patients, 2 "satisfied" patients and no "unsatisfied" patient. Fusion of the subtalar joint was observed in all patients by 12 weeks and in 5 of them as soon as 8 weeks postoperatively (mean, 9.5 [8-12] weeks). There were no cases of delayed fusion or nonunion of the subtalar joint, superficial or deep infection, neurovascular damage, thromboembolic event, screw breakage, need for hardware removal or revision surgery.

CONCLUSION

This study found that PASTA is a safe and reliable technique for adult patients presenting with symptomatic medial facet talocalcaneal coalition and normal hindfoot alignment, demonstrating and maintaining clinical improvement at an average follow-up of 2 years.

LEVEL OF EVIDENCE

Level IV, case series.

Subtalar arthrodesis using a single compression screw: a comparison of results between anterograde and retrograde screwing

INTRODUCTION

The primary objective of this study was to compare the radiological and clinical results of anterograde and retrograde screwing in subtalar arthrodesis using a single compression screw. The secondary objective was to evaluate the subjective results and consolidation of this procedure. The hypotheses were that isolated screw fixation was sufficient to achieve good consolidation and that there was no difference between the two techniques with a similar rate of bone fusion.

METHODS

This is a monocentric, retrospective, radio-clinical study based on 99 patients (101 feet), 58 males and 41 females, with an average age of 64 years. The main aetiology was post-traumatic osteoarthritis, which represented 51% of cases. Two groups were formed: group A (52 feet) consisting of fixed arthrodesis with ascending (retrograde) screwing and group D (49 feet) consisting of fixed arthrodesis with descending (anterograde) screwing. The two groups were statistically comparable in terms of demographic data as well as aetiologies and comorbidities. Arthrodeses which were not fused at 6 months were reassessed at one year and in the event of any radio-clinical doubt regarding consolidation, an additional CT scan was prescribed. Average post-operative follow-up was 11 ± 5 years (2-27 years).

RESULTS

Ninety-two arthrodeses (93%) were fused at one year and 9 were considered to be in non-union, 5 (9.8%) in group A, and 4 (8.3%) in group D. We recorded 30 complications, 22 of which were due to a conflict with the screw head, 18 (34.5%) in group A and 4 (8.3%) in group D (p = 0.03). Conflict between the screw head and the heel led to the removal of the screw after consolidation of the arthrodesis. The clinical results were evaluated using Odom's criteria. Nine per cent of patients described their results as excellent, 29% as good, 51% as satisfactory and 11% found the result to be poor.

CONCLUSION

The fusion rate for isolated compression screw arthrodesis is good, and there is no difference between anterograde and retrograde screws. However, the discomfort caused by the screw head being insufficiently embedded in the retrograde group led to a non-negligible number of additional surgeries to remove the screw.

Midterm Outcome of Subtalar Joint Revision Arthrodesis

BACKGROUND

The outcomes of revision subtalar arthrodesis have received relatively little focus in research compared with primary subtalar arthrodesis outcomes. This study aimed to assess the midterm clinical and radiologic results of subtalar joint revision arthrodesis and to analyze the risk factors that might influence the outcome of this procedure.

METHODS

We performed a retrospective review of 20 patients after subtalar joint revision arthrodesis for malunion, using interposition of iliac crest bone graft. The mean age was 55.75 years and the average follow-up lasted for 48.93 months. Eighty-five percent of the patients had at least 1 risk factor identified prior to revision. Patients' satisfaction and functional outcomes were evaluated with the American Orthopaedic Foot & Ankle Society Scale (AOFAS), the Foot and Ankle Outcome Score (FAOS), the Foot Function Index (FFI), and dynamic pedobarography.

RESULTS

A fusion rate of 80% was recorded whereas 20% of the cases ended with a painful pseudarthrosis requiring additional surgery. Pedobarographic measurements demonstrated that loading has a propensity toward the lateral column, but no substantial effect on the gait of patients. In this group, the following patient-reported outcomes were observed: 70% of the patients were satisfied, 20% of the patients found the result fair, and 10% were not satisfied with the results. Compared with the preoperative evaluation, postoperative functional scores showed significant improvement on the FOAS, AOFAS, and FFI outcome scales.

CONCLUSION

Revision arthrodesis of the subtalar joint remains a challenging issue with a relatively high rate of nonunion, especially in a population of patients with multiple risk factors.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

How many screws are necessary for subtalar fusion? A retrospective study

BACKGROUND

Biomechanical studies have shown a higher compressive force and higher torsional stiffness for fixation with three screws compared to two screws. However, clinical data to compare these fixation techniques is still lacking.

METHODS

A retrospective analysis of 113 patients was performed, who underwent isolated subtalar fusion between January 2006 and April 2018.

RESULTS

Revision arthrodesis was required in 8% (n=6/36) for 3-screw-fixation and 38% (n=35/77) for 2-screw-fixation. For 3-screw-fixation, non-union, was observed in 14% (n=5/36) compared to 35% (n=27/77) in 2-screw fixation. Non-union (p=.025) and revision arthrodesis (p=.034) were significantly more frequent in patients with 2 screws. A body mass index ≥30kg/m² (p=.04, OR=2.6,95%CI:1.1-6.3), prior ankle-fusion (p=.017,OR=4.4,95%CI:1.3-14.5) and diabetes mellitus (p=.04,OR=4.9,95%CI:1.1-17.8) were associated with a higher rate of revision arthrodesis.

CONCLUSIONS

Our findings suggest that successful subtalar fusion is more reliably achieved with use of three screws. However, future prospective studies will be necessary to further specify this recommendation.

Prognostic risk factors for complications associated with tibiotalocalcaneal arthrodesis with a nail

BACKGROUND

Tibiotalocalcaneal (TTC) arthrodesis with a nail can be an effective salvage procedure for several foot and ankle pathologies, but has a relatively high complication rate. The purpose of this study is to investigate risk factors associated with complications after TTC arthrodesis with a nail.

METHODS

Clinical and radiographic outcomes for 82 patients from 2012 to 2016 who underwent TTC arthrodesis with a nail were retrospectivelyevaluated to determine if patient or surgeon specific variables offered prognostic value in predicting negative outcomes.

RESULTS

Diabetes, diabetic neuropathy, high (>2) American Society of Anesthesiologists (ASA) classification, and Charcot neuroarthropathy all were predictive of developing a nonunion in either the subtalar ortibiotalar joints (p<0.05). Diabetic neuropathy was predictive ofreoperation, and along with HbA1C >7.5 was also predictive of hardwarefailure. The odds ratio (OR) for diabetic neuropathy was 2.99 (p<0.05)for nonunion in the tibiotalar or subtalar joints, 3.46 (p<0.05) for reoperation,and 4.11 (p<0.05) for hardware failure. High ASAclassification had an odds ratio of 3.93 (p<0.05) for nonunion in the tibiotalar or subtalar joints as well. Diabetes had an odds ratio of 2.57 (p<0.05) for nonunion.

CONCLUSIONS

Patients with diabetic neuropathy, Charcot neuroarthropathy, elevated HbA1C, and ASA classification >2 demonstrated a higher complication rate in patients undergoing TTC arthrodesis with a nail.

Pulsed Electromagnetic Field Therapy Improves Osseous Consolidation after High Tibial Osteotomy in Elderly Patients-A Randomized, Placebo-Controlled, Double-Blind Trial

Extremely low-frequency pulsed electromagnetic field (ELF-PEMF) therapy is proposed to support bone healing after injuries and surgical procedures, being of special interest for elderly patients. This study aimed at investigating the effect of a specific ELF-PEMF, recently identified to support osteoblast function in vitro, on bone healing after high tibial osteotomy (HTO). Patients who underwent HTO were randomized to ELF-PEMF or placebo treatment, both applied by optically identical external devices 7 min per day for 30 days following surgery. Osseous consolidation was evaluated by post-surgical X-rays (7 and 14 weeks). Serum markers were quantified by ELISA. Data were compared by a two-sided t-test (α = 0.05). Device readouts showed excellent therapy compliance. Baseline parameters, including age, sex, body mass index, wedge height and blood cell count, were comparable between both groups. X-rays revealed faster osseous consolidation for ELF-PEMF compared to placebo treatment, which was significant in patients ≥50 years (∆_mean = 0.68%/week; p = 0.003). Findings are supported by post-surgically increased bone-specific alkaline phosphatase serum levels following ELF-PEMF, compared to placebo (∆_mean = 2.2 µg/L; p = 0.029) treatment. Adverse device effects were not reported. ELF-PEMF treatment showed a tendency to accelerate osseous consolidation after HTO. This effect was stronger and more significant for patients ≥50 years. This ELF-PEMF treatment might represent a promising adjunct to conventional therapy supporting osseous consolidation in elderly patients. Level of Evidence: I.

Subtalar Arthrodesis with Use of Adipose-Derived Cellular Bone Matrix Compared with Autologous Bone Graft: A Multicenter, Randomized Controlled Trial

UPDATE

This article was updated on November 7, 2019, because of a previous error. On page 1909, in the section entitled "Discussion," the sentence that had read "Radiographic nonunion rates of 69.2% and 45.6% were observed at 6 months for ACBM and autograft, respectively, as measured on CT scans; however, these nonunion rates do account for patients who were considered to have attained fusion according to traditional methods, including absence of pain and swelling and presence of arthrodesis on radiographs" now reads "Radiographic nonunion rates of 69.2% and 45.6% were observed at 6 months for ACBM and autograft, respectively, as measured on CT scans; however, these nonunion rates do not account for patients who were considered to have attained fusion according to traditional methods, including absence of pain and swelling and presence of arthrodesis on radiographs."An erratum has been published: J Bone Joint Surg Am. 2019 XXX.

BACKGROUND

Subtalar arthrodesis effectively treats subtalar joint arthritis when other interventions have failed. Nonunion is a known complication of subtalar arthrodesis, with reported rates ranging from 5% to 45%. Historically, open arthrodesis has been performed with use of autologous bone graft; however, there are inherent disadvantages to autologous bone graft, including donor-site morbidity. Mesenchymal stem cells, when placed on a cellular scaffold, have shown promise as an alternative to autologous bone graft. The purpose of this multicenter, randomized controlled trial was to assess the safety and efficacy of an adipose-derived cellular bone matrix (ACBM) composite made with live cells compared with autograft in subtalar arthrodesis.

METHODS

A total of 140 patients were enrolled in a prospective, randomized (1:1) controlled trial performed at 6 clinical sites in the U.S. End points, including radiographic, clinical, and functional outcomes, were assessed over 2 years of follow-up.

RESULTS

A total of 109 patients underwent arthrodesis with ACBM (52 patients) and autograft (57 patients). At 6 months, fusion was achieved in 16 patients (30.8%) in the ACBM group and 31 patients (54.4%) in the autograft group as measured on computed tomography (p = 0.024), and in 41 patients (78.8%) in the ACBM group and 50 patients (87.7%) in the autograft group as assessed on clinical and radiographic evaluation (p = 0.213). Quality-of-life outcome measures demonstrated significant functional improvement from baseline for both groups. Fewer cases of serious adverse events occurred in the autograft group (10.5%) compared with the ACBM group (23.1%) (p = 0.078).

CONCLUSIONS

In patients who require subtalar arthrodesis, the use of ACBM demonstrated lower rates of radiographic fusion compared with treatment with autograft. The nonunion rate in the autologous group, as measured on computed tomography, was high. Good clinical outcomes were achieved in spite of the high non-union rates.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Revision of Failed Total Ankle Replacement With a Custom 3-Dimensional Printed Talar Component With a Titanium Truss Cage: A Case Presentation

An innovative technique is presented for salvage of a failed total ankle replacement resulting from talar subsidence with the use of a custom 3-dimensional printed articulating talar component with a titanium truss cage. This introduces a better alternative to an ankle arthrodesis with which ankle joint function and range of motion may be preserved.

Management of Calcaneal Fracture Malunion with Bone Block Distraction Arthrodesis: A Systematic Review and Meta-Analysis

One of the most severe complications in calcaneal fractures is a malunion. When a malunion occurs, subtalar bone block distraction arthrodesis provides restoration of calcaneal height, length, correction of varus deformity, and elimination of subtalar joint arthritis. A systematic review showed the union rate for all procedures was 95.78%. The overall complication rate was 38% for all procedures. This is the first study to categorically break down complications with statistical analysis. The data presented indicate the level of difficulty of the subtalar distraction bone block arthrodesis for calcaneal malunions and may even suggest the need for newer techniques.

Endoscopic Revision Subtalar Arthrodesis

Varus malunion after subtalar arthrodesis is considered to be the worst deformity in hindfoot alignment. Poor clinical outcome is expected if there is more than 10° of varus malunion with lateral column overload. Open revision subtalar arthrodesis is associated with high rates of complications, especially involving soft tissue and nonunion. The purpose of this Technical Note is to describe the technical details of endoscopic revision subtalar arthrodesis in which the correction of varus malunion is performed with a minimally invasive technique, which may reduce the risk of soft tissue complications and nonunion.

Open Technique for In Situ Subtalar Fusion

The subtalar joint plays an important role for the hindfoot when accommodating during gait. Joint degeneration may be caused by posttraumatic, inflammatory, and pathologic biomechanical changes. Once conservative treatment has failed, subtalar fusion should be considered. The indication for surgery is based on thorough clinical and radiographic evaluation. Several techniques for subtalar fusion are published in literature. This article aims to describe a technique for in situ arthrodesis of the subtalar joint, paying special attention to biomechanical aspects as well as preoperative clinical and radiological work-up.

Subtalar Arthroscopic Fusion

Arthroscopic subtalar fusion is an excellent approach to subtalar pathologic condition where conservative treatment has failed and a fusion has been indicated. Formal contraindications include excessive malalignment and bone loss. The posterior arthroscopic approach is analyzed in this article, including indications, surgical technique, surgical tips, and complications. Excellent results can be expected, including a shorter time to fusion, and faster rehabilitation, including activities of daily living and sports.

Arthroscopic posterior subtalar arthrodesis for salvage of posttraumatic arthritis following calcaneal fractures

BACKGROUND

Subtalar arthrodesis is a treatment option for pain due to posttraumatic arthritis following calcaneal fractures. The goal of this study is to examine the results of arthroscopic subtalar arthrodesis for posttraumatic arthritis following calcaneal fractures.

PATIENTS AND METHODS

We performed a retrospective case series reviewing 37 consecutive patients (36 male) treated for posttraumatic arthritis following calcaneal fractures by arthroscopic subtalar arthrodesis. The fractures were due to high-energy injuries in 81% of cases, and 12 fractures (32.4%) had been previously treated with internal fixation. Average follow-up was 57.5 months.

RESULTS

Average American Orthopedic Foot and Ankle Society (AOFAS) scores significantly improved from 49.0 ± 10.9 points preoperatively to 76.0 ± 8.0 points at final follow-up. Average time to union was 12.5 weeks. Six patients (16.2%) suffered complications: superficial wound infection (2.7%), symptomatic hardware that warranted removal (5.4%) and nonunion (8.1%) presented nonunion. All three cases had prior internal fixation through an extensile lateral approach, and fused after a repeat surgery.

CONCLUSION

Arthroscopic subtalar arthrodesis offers consistent improvement in cases of posttraumatic arthritis following calcaneal fractures, with a union rate similar to published series of open arthrodesis. We observed more nonunions in patients who had been treated previously with internal fixation. In spite of this, we continue to recommend arthroscopic subtalar arthrodesis, as it preserves the soft tissue envelope better than open techniques.