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

Risk factors associated with subtalar fusion within 5 years following calcaneal ORIF

BACKGROUND

Although most calcaneal fractures are managed with open reduction internal fixation (ORIF), they can ultimately lead to subtalar arthritis and pain requiring subtalar fusion when conservative treatments prove ineffective. Understanding the risk factors associated with subtalar fusion (STF) after calcaneal ORIF is crucial for optimizing patient outcomes and treatment strategies. This study aimed to comprehensively evaluate these risk factors and their association with the incidence of STF, including patient demographics, medical comorbidities, same day and 90-day reimbursement data.

METHODS

A retrospective analysis was performed using the PearlDiver Mariner 157 national claims database from January 1st, 2010 to October 31st, 2021. Patients who underwent calcaneal ORIF, identified using Current Procedural Terminology (CPT) and ICD Procedure Codes were queried for 5-year rates of STF and reimbursement data. Patient demographics and comorbidities were recorded, and multivariate logistic regression was employed to determine the association of risk factors with STF.

RESULTS

Patients with STF had a higher proportion of alcohol abuse (21.3 % vs. 16.2 %), depression (58.1 % vs. 43.1 %), drug abuse (29.1 % vs. 19.7 %), obesity (40.3 % vs. 28 %) and tobacco use (62.2 % vs. 50.3 %), all exhibiting a p-value of less than 0.001. Those with depression (OR: 1.54; 99 % CI:1.29-1.84; P < 0.001) and obesity (OR:1.58; 99 % CI: 1.32-1.88; P < 0.001) as comorbidities had a higher odds ratio of association with STF following calcaneal ORIF.

CONCLUSION

Patients who ultimately require STF within 5 years of calcaneal ORIF had higher rates of alcohol abuse, tobacco use, drug use, obesity, and depression. There was no significant difference observed between those with and without STF in average same-day and 90-day reimbursements and demographics.

Secondary Subtalar Arthrodesis: Surgical Outcome and Predictors of Functional Outcome and Quality of Life After Bone Block Distraction vs In Situ Technique

Background

The outcome of a secondary subtalar arthrodesis after prior calcaneal fracture has been widely described. However, the surgical treatment has evolved significantly over the past decade, paralleling the shifts observed in primary repair strategies. Therefore, we describe the outcome following a secondary arthrodesis after an intra-articular calcaneal fracture, comparing the in situ (ISA) and bone block distraction arthrodesis (BBDA) techniques.

Methods

In total, 339 patients who underwent a subtalar arthrodesis between January 1998 and November 2022 were screened for eligibility. Inclusion criteria were age ≥16 years, having undergone a subtalar arthrodesis following a calcaneal fracture, and a minimal follow-up of 1 year. Exclusion criteria were subtalar arthrodesis before January 2010 and a subtalar arthrodesis within 6 weeks of injury. A total of 259 patients did not meet the inclusion criteria, resulting in the inclusion of 80 patients with 82 fractured calcanei.

Results

No significant differences between ISA and BBDA in surgical outcome were seen. Subtalar fusion was achieved in 78 of the patients (95.1%). Additionally, a deep surgical site infection occurred in 6 patients (7.8%). The American Orthopaedic Foot & Ankle Society ankle-hindfoot scale (AOFAS) and Foot Function Index (FFI) scores and the EuroQol-5 dimensions (EQ5D) index were similar between the 2 groups. However, a significantly higher EQ5D-VAS was reported by the subjects who received a BBDA (median [interquartile range], 70.0 [52.0-82.0] vs 81.0 [70.0-90.3], P = .021). Multiple regression revealed that a higher Böhler angle before the initial fracture reconstruction significantly improved the AOFAS score, whereas the FFI significantly improved by an initial conservative treatment and implant removal after arthrodesis. Finally, increasing age significantly improved the EQ5D index.

Conclusion

Our study presents comparable surgical outcomes between ISA and BBDA for secondary subtalar arthrodesis following calcaneal fractures. Functional outcomes, as measured by the AOFAS and FFI scores, were also similar between the 2 techniques, although patients undergoing BBDA reported higher EQ5D visual analog scale scores.

Level of Evidence

Level III, retrospective cohort study.

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.