Correlation of Functional Outcomes and Sagittal Alignment After Long Instrumented Fusion for Degenerative Thoracolumbar Spinal Disease

OBJECTIVEFew studies have addressed that dynamic sagittal imbalance can develop distal to the spinal fusion and cause sagittal malalignment, unlike proximal junctional kyphosis (PJK) in the proximal portion. The purpose of this study was to investigate risk factors between the 2 different types of postoperative sagittal imbalance after long fusion to the sacrum for the treatment of degenerative sagittal imbalance (DSI).METHODSEighty patients who had undergone surgical correction for DSI were included. Radiographic measurements included spinopelvic parameters on whole-spine plain radiographs and degeneration of paravertebral muscles on MRI. Univariate and multivariate analyses for clinical and radiological factors were conducted for respective risk factors. In subgroup analyses, the 2 different types of postoperative sagittal imbalance were directly compared.RESULTSForty patients (50%) developed postoperative sagittal imbalance; of these patients, 22 (55.0%) developed static proximal kyphosis from PJK, and 18 patients (45.0%) developed dynamic sagittal imbalance without PJK. The independent risk factors in proximal kyphosis were greater postoperative pelvic tilt (HR 1.11) and less change in sacral slope (SS) (HR 1.09), whereas there were more fusion levels (HR 3.11), less change in SS (HR 1.28), and less change in thoracic kyphosis (HR 1.26) in dynamic sagittal imbalance. Directly compared with the proximal kyphosis group, dynamic sagittal imbalance was more commonly found in patients who had less correction of sagittal parameters as well as fatty atrophy of the paravertebral muscles. Clinical outcomes in the dynamic sagittal imbalance group were superior to those in the proximal kyphosis group.CONCLUSIONSOptimal correction of sagittal alignment should be considered in long instrumented fusion for DSI, because insufficient correction might cause one of 2 different types of postoperative sagittal imbalance at different sites of decompression. Dynamic sagittal imbalance compared with proximal kyphosis was significantly associated with less correction of sagittal alignment, in conjunction with more fusion levels and degeneration of the paravertebral muscles.

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TL 18052 - Sagittal tibiotalar alignment in fixed-bearing total ankle replacement

Scientific Journal of the Foot & Ankle ◽

10.30795/scijfootankle.2019.v13.1008 ◽

2019 ◽

Vol 13 (Supl 1) ◽

pp. 66S

Author(s):

Guilherme Honda Saito ◽

Natalie Nielsen ◽

Austin Sanders ◽

Scott Ellis ◽

Carolyn Sofka ◽

...

Keyword(s):

Functional Outcomes ◽

Sagittal Alignment ◽

Total Ankle Replacement ◽

Fixed Bearing ◽

Implant Positioning ◽

Radiographic Measurements ◽

Ankle Replacement ◽

Outcome Scores ◽

The Difference

Introduction: Implant positioning is critical in total ankle replacement (TAR). However, the effect of sagittal tibiotalar alignment on functional outcomes in fixed-bearing TAR remains unclear. Furthermore, no studies comparing different fixed-bearing implants with respect to the anteroposterior position of the talar component have been performed to date. Methods: A retrospective analysis of 71 primary TARs in a single center was performed. Prostheses included were the INBONE II® (Wright Medical, Memphis, TN) and the Salto Talaris (Integra LifeSciences, Plainsboro, NJ). Radiographic measurements of the tibial-axis-to-talus ratio (T-T ratio) and the anteroposterior offset ratio (AP offset ratio) were performed preoperatively and postoperatively, respectively. Foot and Ankle Outcome Scores (FAOS) and SF-12 MCS and PCS scales were evaluated preoperatively and 2 years postoperatively. Results: Postoperative sagittal tibiotalar alignment was neutral in 39 ankles and anterior in 32 ankles. No significant differences were observed between groups with respect to clinical outcome scores. Patients with a Salto Talaris prosthesis had a greater AP offset ratio (0.12 ± 0.05) than patients with an INBONE II® implant (0.05 ± 0.04) (P < .01); however, this increased translation did not correlate with the outcome scores. Conclusion: At the 2-year follow-up, the INBONE II® TAA showed a more neutral sagittal alignment compared with the Salto Talaris prosthesis. However, no correlation between the postoperative AP offset ratio and functional outcome scores was observed with the use of the two fixed-bearing TAR. Further studies with longer follow-ups are needed to determine if the difference in sagittal alignment may have an effect on functional outcomes in the long-term.

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