Superior Tuber Displacement in Intra-articular Calcaneus Fractures.
BACKGROUND
Intra-articular calcaneus fractures result in heel shortening, widening, varus malalignment, and loss of height. Little has been written regarding superior displacement of the calcaneal tuber, which warrants consideration as previous literature has demonstrated issues arising from a shortened triceps surae. We sought to determine the amount of tuber elevation seen in calcaneus fractures as compared to normal calcanei and propose 2 new measurements that aid in quantifying displacement and may aid in the surgical management of calcaneus fractures.


METHODS
Lateral radiographs of 220 normal calcanei were examined. Two novel measurements, the talo-tuber angle and talo-tuber distance, were used to establish normative data for calcaneal tuber positioning. Lateral radiographs of 50 calcaneus fractures treated operatively were examined and the same measurements were obtained before and after surgery to determine the amount of superior tuber elevation.


RESULTS
Normative data demonstrated a mean of 38.6 degrees (±SD = 4.3, range: 26.2-58.4) when using the talo-tuber angle and 54.5 mm (±SD = 7.3, range: 36.2-72.6) when using the talo-tuber distance in normal calcanei. Patients sustaining calcaneus fractures demonstrated a mean of 29.5 degrees (±SD = 5.9, range: 20-46.4) for the talo-tuber angle and 39.0 mm (±SD = 9.4, range: 24.0-62.9) for the talo-tuber distance. These values changed to a mean of 37 degrees (±SD = 5.2, range: 26.4-50) for the talo-tuber angle and 51.8 mm (±SD = 8.6, range: 33.2-75.7) for the talo-tuber distance after surgery. There was a statistically significant difference (P value < .01) for both talo-tuber angle and distance between normal and fractured calcanei. Inter- and intra-observer agreement was excellent.


CONCLUSIONS
Superior displacement of the calcaneal tuber is a deformity seen in intra-articular calcaneus fractures that has been poorly described that warrants increased awareness and correction at the time of surgery. We propose 2 novel measurements with associated normative data that may aid surgeons in quantifying this deformity and assessing anatomic reduction.


METHODS
Level III, comparative study.
Harvard Medical School, BIDMC, Carl J. Shapiro Department of Orthopaedics, Boston, MA, USA mghorban@bidmc.harvard.edu.
Mohammad
M
Ghorbanhoseini
Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran.
Azadeh
A
Ghaheri
Harvard Medical School, BIDMC, Carl J. Shapiro Department of Orthopaedics, Boston, MA, USA.
Kempland C
KC
Walley
Harvard Medical School, BIDMC, Carl J. Shapiro Department of Orthopaedics, Boston, MA, USA.
John Y
JY
Kwon
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002111:Calcaneus / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology / Q000601:surgery; D005260:Female; D005529:Foot Bones / Q000000981:diagnostic imaging / Q000473:pathology; D018409:Foot Injuries / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D000072039:Fracture Dislocation / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D057072:Intra-Articular Fractures / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D055815:Young Adult
calcaneal tuber superior displacement; intra-articular calcaneus fracture; talo-tuber angle; talo-tuber distance; triceps surae weakness