Restoration of calcaneal anatomy and physiologic function after fracture: the importance of tuber length.

OBJECTIVES

To evaluate calcaneal tuber length (TL) and its influence on calcaneal height (CH), talar declination angle (TDA), and function during plantarflexion after operative fixation of calcaneus fractures.

DESIGN

Retrospective case-control study.

SETTING

Large, urban, level 1 trauma center.

PATIENTS/PARTICIPANTS: A total of 39 patients from 2012 to 2022 with isolated intra-articular calcaneus fractures with weight-bearing lateral postoperative and contralateral x-rays (to use as internal control) with at least 1 year follow up.

INTERVENTION

Patients underwent fixation of calcaneus fractures and were separated into "short tuber" (ST) and "restored tuber" (RT) groups. Postoperative radiographs were compared with contralateral radiographs.

MAIN OUTCOME MEASUREMENTS

Calcaneal Bohler angle (BA), TL, CH, TDA, and relative work increase using the equation Work = Force × Distance. Fixation methods related to TL were also investigated.

RESULTS

Overall, 37 of 39 patients (95%) had postoperative BA within 20-40°. 8 of 39 patients were in the ST group, and 31 of 39 were in the RT group. The average TL difference was 0.73 cm in ST versus 0.13 cm in RT ( < 0.01). The average CH difference was 0.46 cm in ST versus 0.28 cm in RT ( = 0.04). The average TDA difference was 9.9° in ST (flatter) versus 2.6° in RT ( = 0.024). The average work increase to plantarflex the ankle was 12.1% in ST versus 2.2% in RT ( < 0.01). Open fixation resulted in shorter TLs compared with the contralateral side ( = 0.02), but percutaneous fixation did not ( = 0.17).

CONCLUSIONS

Despite restoring BA, presence of a shortened tuber can still result in decreased CH and a flat talus compared with the contralateral limb. It also required increased work to plantarflex the ankle, further highlighting the importance of restoring tuber length.

LEVEL OF EVIDENCE

IV.