Isolated Arthroscopic-Assisted Subtalar Fusion: A Systematic Review

Subtalar Arthrodesis in Patients With Prior Tibiotalar Arthrodesis for Posttraumatic Osteoarthritis

BACKGROUND

The tibiotalar arthrodesis for end-stage ankle osteoarthritis is a surgical procedure that leads to a modification of the kinematics of the adjacent joints and may result in the development of secondary osteoarthritic degeneration of the subtalar joint. It has previously been observed that subtalar arthrodesis in this context shows a lower fusion rate than isolated subtalar arthrodesis. This retrospective study reports the results of subtalar joint arthrodesis with previous ipsilateral tibiotalar arthrodesis and suggests some factors that may compromise the fusion of the joint.

METHODS

Between September 2010 and October 2021, 15 arthrodeses of the subtalar joint with screw fixation were performed in 14 patients, with a fusion of the ipsilateral tibiotalar joint. Fourteen of 15 cases used an open sinus tarsi approach, 13 were augmented with iliac crest bone graft, and 11 had supplemental demineralized bone matrix (DBM). The outcome variables were fusion rate, time to fusion, and revision rate. Fusion was assessed by radiographs and computed tomography scan.

RESULTS

Twelve of the 15 subtalar arthrodeses (80%) fused at the first attempt with an average fusion time of 4.7 months.

CONCLUSION

In this limited retrospective case series, compared to the fusion rate of isolated subtalar arthrodesis reported in the literature, the rate of subtalar fusion in the presence of an ipsilateral tibiotalar arthrodesis was found to be lower.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

An Umbrella Systematic Review and Meta-Analysis of Systematic Reviews on the Topic of Foot and Ankle Arthrodesis Nonunion Rates

The purpose of this systematic review and meta-analysis was to appraise and combine the available systematic reviews reporting nonunion incidence and prevalence in foot and ankle arthrodesis procedures. The Cochrane Library and MEDLINE were searched for relevant systematic reviews from inception to January 2022. Two independent reviewers selected and reviewed eligible studies. Studies were included if they were systematic reviews or meta-analyses reporting nonunion incidence and prevalence in foot or ankle arthrodesis procedures. Fourteen systematic reviews of 8 types of joint arthrodesis procedures were included for meta-analysis. These reviews comprised 138 studies with 5793 joint arthrodesis procedures. Quality of the included reviews were assessed using the AMSTAR2 checklist. Overall and subgroup meta-analysis of prevalence were performed using random effects model. Publication bias was determined by evaluation of a DOI plot with the Luis Furuya-Kanamori index of asymmetry. The pooled prevalence for foot and ankle nonunion rate was 8.1% (95% confidence interval [CI] 6.5%-9.9%). Overall prevalence of nonunion for single joint foot and ankle joint arthrodesis was 6.1% (95% CI 4.8%-7.6%). Subgroup analysis found that the highest rate of nonunion occurred during tibiotalocalcaneal arthrodesis with 27.1% (95% CI 19.4%-35.2%). We have reported the first meta-analysis of systematic reviews on nonunion rates in foot and ankle arthrodesis procedures. The overall nonunion rate for foot and ankle arthrodesis procedures was 8.1%. For single joint fusion procedures, the nonunion prevalence was 6.1%. Our reported nonunion rates are lower than previously published numbers.

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.