The positive predictive value of ankle fracture diagnosis in the Danish National Patient Registry

INTRODUCTION

Information on data validity is essential for understanding the precision of studies based on data from the Danish National Patient Registry (DNPR). Thus, the aim of this study was to validate the quality of ankle fracture data in the DNPR.

METHODS

We identified all patients from four hospitals with a surgically treated ankle fracture between 1 January 2018 and 31 December 2018. The positive predictive value (PPV) was estimated for a random sample of 10% of patients with both a relevant ankle fracture diagnosis code and a relevant procedure code, as well as for patients with only a relevant ankle fracture diagnosis code or a relevant ankle fracture procedure code. We collected data from medical records and X-rays. Two consultants independently validated the ankle fracture diagnosis and procedure codes reported to the DNPR.

RESULTS

Among the four centres, 651 patients were identified with both an ankle fracture diagnosis and a procedure code. Among these, data from 65 (10%) patients were extracted for validation. For these patients, the PPV for an ankle fracture was 0.95 (95% confidence interval (CI): 0.88-0.99). The PPV for the diagnosis code was 0.89 (95% CI: 0.79-0.95), and for the procedure code, the PPV was 0.82 (95% CI: 0.70-0.90). For patients with only an ankle fracture diagnosis code or only a surgical procedure code, the PPV for an ankle fracture was 0.77 (95% CI: 0.64-0.87).

CONCLUSION

This study showed that ankle fracture diagnosis and procedure codes registered in the DNPR are of a high quality and thus constitute a valuable data source for research on ankle fractures.

FUNDING

none.

TRIAL REGISTRATION

The Danish Data Protection Agency approved the study (journal number 2015-18/62866).

Should we bury K-wires after metacarpal and phalangeal fracture osteosynthesis?

BACKGROUND

Burying Kirschner wires (K-wires) under the skin after metacarpal and phalangeal fracture osteosynthesis may reduce risk of infection, but it might also complicate later removal.

PURPOSE/AIM OF STUDY

To examine infection and reoperation rates after metacarpal and phalangeal fracture osteosynthesis with buried versus exposed K-wires.

MATERIALS AND METHODS

Metacarpal and phalangeal fractures treated with K-wire osteosynthesis at our institution from 1st of January, 2009 to 1st of February, 2015 were identified retrospectively. The final study population included 444 patients, 331 with metacarpal, 109 phalangeal and 4 with mixed fractures. Surgical and patient records were examined 90 days postoperatively.

FINDINGS/RESULTS

337 patients (75.9%) were treated with buried K-wires and 107 patients (24.1%) with exposed (non-buried) K-wires. 14 patients (4.1%) treated with buried K-wires presented with postoperative infection, opposed to 7 patients (6,5%) treated with non-buried K-wires (p = 0.311). None of the postoperative infections caused re-operation. Only one case of deep/severe infection was recorded in a patient treated with buried K-wires requiring intravenous antibiotic treatment. In 58 of 337 patients (17.2%) treated with buried K-wires, removal was not possible in the outpatient clinic and required readmission for removal in the operation theatre. All exposed K-wires could be removed in the out-patient clinic without re-operation.

CONCLUSIONS

We found no difference in postoperative infection rate between metacarpal and phalangeal fracture osteosynthesis with buried versus exposed K-wires. However, the high readmission and reoperation rate (17.2%) after burying K-wires should call for reconsideration of surgical strategies.