A coronal plane fracture of the femoral condyle (creating a so-called Hoffa
fragment) has been well described in association with fractures of the
supracondylar-intercondylar region of the distal part of the
femur1. This
fracture has implications with regard to preoperative planning, the choice of
surgical approach, implant selection, and functional outcomes.
Coronal plane fractures of the distal part of the femur are markers of
high-energy injury mechanisms. Their presence warrants a thorough workup for
other injuries associated with high-energy trauma such as fractures of the
spine, pelvis, femoral neck, tibial plateau, ankle, and calcaneus. A Hoffa
fracture can often be missed on plain radiographs. Nork et al. showed that up
to 30% of coronal plane fractures were missed on plain radiographs of distal
femoral fractures, often necessitating the use of computerized tomography for
identification and preoperative
planning2.
While the association of a Hoffa fragment with a
supracondylar-intercondylar femoral fracture has been well characterized, we
are unaware of any previous reports on the isolated occurrence of a coronal
plane fracture of a femoral condyle in association with an ipsilateral femoral
shaft fracture. We report on a patient who sustained a femoral shaft fracture
with an ipsilateral coronal plane fracture of the medial femoral condyle. The
patient was informed that data concerning the case would be submitted for
publication.
A thirty-three-year-old right-hand-dominant man was riding a motorcycle
when he was struck by a tractor trailer. He was immediately transported to a
level-I trauma center, where he described severe pain in the left leg and arm.
Gross deformities of the left arm and thigh were identified on physical
examination. Both injuries were closed, and both extremities were
neurovascularly intact. A transverse fracture of the left humerus was treated
with a coaptation splint. A small effusion was present in the left knee, but
there was no discrete tenderness to palpation over the patella or the medial
or lateral joint lines. An anteroposterior radiograph of the left femur
revealed a midshaft transverse fracture
(Fig. 1). A skeletal traction
pin was placed in the distal part of the left femur for provisional
stabilization. After traction was applied, a radiograph of the left knee
revealed a nondisplaced Hoffa fragment of the medial femoral condyle and a
proximal fibular fracture (Fig.
2). The patient was taken to the operating room for definitive
fixation of the left femoral fractures.
General anesthesia was administered, and the patient was placed supine on a
radiolucent operating table. Before fixation of the fractures, the femoral
shaft fracture was stabilized manually by one surgeon while a second assessed
the knee. The knee was stable through a full range of motion and to both varus
and valgus stress. The coronal plane fracture of the medial femoral condyle
was confirmed under fluoroscopy. No fracture of the femoral head, neck, or
intertrochanteric region was present. The patient underwent intramedullary
nailing of the femoral shaft fracture with an antegrade piriformis locked
femoral nail without complications (Fig.
3). We purposely used a femoral nail that was slightly shorter
than usual so that its distal tip would not displace the medial condyle
fracture, which was monitored fluoroscopically throughout the femoral nailing
procedure. One proximal and two distal locking bolts were then placed without
disruption of the Hoffa fragment.
The coronal plane fracture was addressed next. Internal fixation was
performed with two screws placed under fluoroscopy from anterior to posterior,
and good alignment of the condylar fracture was achieved
(Figs. 4-A and 4-B). The knee
was reexamined and noted to be stable. There was no displacement of the
fracture with stability testing.
Postoperatively, the patient remained non-weight-bearing for six weeks but
was allowed to begin active and passive range-of-motion exercises on the first
postoperative day. At the most recent follow-up examination (at three months),
the patient reported no pain at the knee or hip. Physical examination revealed
a full, painless range of motion of the knee, and radiographs showed good
healing of the fractures with no step-off at the articular surface.
The coronal plane fracture of the femoral condyle was initially described
in 1904 by Hoffa3.
The fracture is often missed on plain radiographs and is best seen on computed
tomographic scans4.
It is important to identify such a fracture because surgical fixation is the
preferred method of treatment; nonoperative management often leads to
malunion, nonunion, and further displacement of the fracture
fragment5. Internal
fixation of unicondylar fractures allows stable reconstruction of the distal
articular surface of the femur and permits an early postoperative range of
motion of the knee with very good long-term
results6-8.
Although isolated bilateral unicondylar and unilateral bicondylar coronal
plane fractures have been described, Hoffa fractures most frequently present
as unilateral, unicondylar injuries associated with a supracondylar or
intercondylar fracture of the distal part of the
femur2,9-11.
This association requires that the orthopaedic surgeon be aware of the
possibility of a coronal plane fracture when a patient presents with a distal
femoral fracture and that the appropriate radiographic workup and preoperative
planning be performed. This possibility of a Hoffa fracture does not
necessarily come to mind when an orthopaedic surgeon sees a patient with an
isolated femoral shaft fracture.
Butler et al. noted three Hoffa fractures in their study of intramedullary
nailing of ipsilateral femoral shaft and distal femoral
fractures12. All
three fractures occurred in association with an intercondylar femoral
fracture. In one patient, the Hoffa fracture was recognized intraoperatively
and open reduction and internal fixation of the fragment was performed prior
to the intramedullary nailing. In the other two patients, the coronal plane
fracture was not discovered until after the intramedullary nailing had been
done. In both of those patients, a second operation was necessary and
posttraumatic arthritis was seen at the time of follow-up. In addition, those
two patients had the lowest knee function scores in the study. The authors
concluded that any patient with an intercondylar fracture should, at the very
minimum, be evaluated with lateral and oblique radiographs of the knee
preoperatively to aid in the detection of a coronal plane fracture.
Barei et al. analyzed fixation techniques for noncontiguous fractures of
the femoral neck, femoral shaft, and distal part of the
femur13. All of the
patients in the study had sustained high-energy injuries and had a Pauwel
type-III (vertical) femoral neck fracture in addition to fractures of the
femoral shaft and the distal part of the femur. The authors emphasized the
need for acute fixation of the femoral neck component of the triad of
injuries, with fixation of the fractures of the shaft and the distal part of
the femur to be performed when the patient's general condition had been
stabilized. Additionally, the authors noted that fixation of the fractures of
the femoral neck and the distal part of the femur frequently dictated the type
of fixation used for the femoral shaft fracture.
We found no reports of an isolated association between a Hoffa fracture and
a femoral shaft fracture in our search of the English-language literature.
This report illustrates that a coronal plane fracture can coexist with an
ipsilateral femoral shaft fracture despite the absence of a supracondylar,
intercondylar, or femoral neck component. We strongly recommend a complete set
of knee radiographs, including anteroposterior, lateral, and oblique views,
for all patients with a femoral shaft fracture in order to avoid missing this
injury. In addition, we make radiographs of the distal part of the femur after
placement of the traction pin. Finally, any knee abnormality, such as
ecchymosis, effusion, or instability, observed during the physical examination
should alert the physician to the possibility of an associated injury and
should trigger a more extensive workup preoperatively as well as a thorough
knee examination intraoperatively.
Ideally, radiographs of the knee should be made before placement of a
traction pin, as the pin could displace a Hoffa fracture fragment, especially
one of the medial condyle. Additionally, a traction pin placed into a Hoffa
fragment would do little to reduce or stabilize it and could contaminate the
fracture site. We were fortunate that neither of these complications occurred
in our patient. Our protocol of obtaining a complete set of knee radiographs
allowed us to identify the unexpected injury preoperatively, adequately plan
the surgical approach, and avoid a reoperation. ?