Bone Defects After Surgery for Displaced Intraarticular Calcaneal Fractures Spontaneously Improve Without Bone Grafting.

BACKGROUND: Most intraarticular displaced calcaneal fractures are accompanied by bone defects after surgical treatment, but the concern about negative effects of bone defects has not been resolved yet owing to the few studies on this issue. Therefore, studies on volumetric changes in bone defects over time and the correlation between postoperative outcomes and residual bone defects will be helpful to address the controversy on the necessity of bone grafting in bone defects of calcaneal fractures. QUESTIONS/PURPOSES: (1) Do bone defects change in size in the first year after surgical treatment of displaced intraarticular calcaneal fractures? (2) Does the size of residual bone defects correlate with postoperative radiographic or clinical outcomes? METHODS: Between 2015 and 2019, 99 patients with displaced intraarticular calcaneal fractures visited the investigators' institution, of whom 95 received surgical treatment. Of the patients treated with surgery, 25% (24 of 95) did not undergo open reduction and internal fixation via an extensile lateral approach, and 19% (18 of 95) had multiple fractures, bilateral fractures, open fractures, or a history of previous surgery on the calcaneus; all of these patients were excluded. During the study period, CT was routinely performed for calcaneal fractures immediately after and 12 months after the surgery, but 6% (6 of 95) of the patients had insufficient CT data due to loss to follow-up before 12 months or other reasons, leaving 47 patients for evaluation in this retrospective study. Fractures were fixed with plate and screws, and bone grafting was not performed in all patients. To answer our first question, which was on the changes in bone defects over time, volumetric measurements of the bone defect were performed using CT via the ITK-SNAP software. The percentage of volumetric change was calculated as a fraction of the volumetric change over 12 months from the initial volume. The percentage of the residual bone defect was calculated as a fraction of the volume of the residual bone defect relative to the volume of the entire calcaneus. To answer our second question, which was on the correlation between residual bone defects and postoperative outcomes, we assessed the Böhler angle, Gissane angle, calcaneal height, Olerud-Molander Ankle Score (OMAS), and VAS score for pain and compared these parameters with the size of the residual bone defect using the Pearson correlation coefficient. The OMAS and VAS scores for pain were evaluated and recorded during patient visits, and we obtained the scores through a chart review. All volumetric measurements and radiographic evaluations were performed by two orthopaedic surgeons, and the intraobserver and interobserver reliability were assessed using the intraclass correlation coefficient. RESULTS: The mean volume of the bone defect measured using CT was 4 ± 3 cm3 immediately after surgery and 1 ± 1 cm3 12 months after surgery. During the first 12 months after surgery, the mean volume of the bone defect was reduced by 77% (95% confidence interval 73% to 80%). The mean residual bone defect in the entire calcaneus was 2% (95% CI 1% to 2%), and none of the postoperative outcomes were correlated with the residual bone defect. CONCLUSION: As bone defects substantially resolve without treatment, surgeons do not need to use bone graft for the surgical treatment of displaced intraarticular calcaneal fractures. Future studies that include patients who underwent bone grafting for the treatment of calcaneal fractures are needed to confirm our findings and to further investigate whether bone grafting has additional benefits for the recovery of bone defects. LEVEL OF EVIDENCE: Level III, therapeutic study.