The treatment of reverse obliquity intertrochanteric fractures with the intramedullary hip nail.
BACKGROUND
Reverse obliquity intertrochanteric fractures have been recognized as having unique anatomic and mechanical characteristics. Even though some clinical reports regarding intramedullary hip nailing for reverse obliquity intertrochanteric fracture show favorable results, there has been no clinical report of intramedullary hip nailing regarding the clinical significance of the lesser trochanteric fragment which differentiates Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) 31-A3.3 from A3.1 and A3.2.


METHODS
We retrospectively reviewed the clinical results of 46 cases of reverse obliquity or transverse intertrochanteric fracture treated with intramedullary hip nails. Twenty-five fractures were fixed with proximal femoral nail (PFN), and 21 fractures were fixed with intertrochanteric subtrochanteric nail.


RESULTS
Among 40 patients, followed up for more than 6 months, 22 31-A3.3 fractures (84.6%) out of 26 and all 14 A3.1 or A3.2 fractures were healed after the first operation. The complications were four cases of fixation failure and one case of femoral shaft fracture after fall. They occurred in the A3.3 type fracture, which were fixed with the PFN. The mean union time was longer in the A3.3 group (5.98 months, range 3-17 months) compared with that in the A3.1 or A3.2 group (4.65 months, range 3-9 months) (p = 0.048). Two cases of reciprocal migration of two screws (Z-effect) required exchange of the femoral neck screw to a shorter one in the PFN group. The amount of sliding of the femoral neck screw of the PFN (6.8 mm, range 0.3 mm-16.5 mm) was greater than that of the intertrochanteric subtrochanteric nail lag screw (1.89 mm, range: 0.2 mm-4.6 mm) (p = 0.012). Statistical analysis showed that the type of implant PFN, fracture subtype (31-A3.3), and old ages (more than 65 years old) significantly prolonged the union time (p < 0.05).


CONCLUSIONS
The lesser trochanteric fragment and posteromedial defect in 31-A3.3 fracture seems to play an important role in the stability after intramedullary hip nailing. The causes of fixation failure in the PFN group were associated with excessive sliding of femoral neck screw, which was aggravated by toggling motion in the 31-A3.3 fractures.
Department of Orthopaedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
Si Yong
SY
Park
Kyu Hyun
KH
Yang
Je Huyn
JH
Yoo
Han Kook
HK
Yoon
Hui Wan
HW
Park
D000058:Accidental Falls; D000063:Accidents, Traffic; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001858:Bone Nails; D015331:Cohort Studies; D005260:Female; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects / Q000379:methods*; D017102:Fracture Healing / Q000502:physiology; D006620:Hip Fractures / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery*; D006801:Humans; D015601:Injury Severity Score; D007870:Leg Length Inequality / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology; D011336:Probability; D011379:Prognosis; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric