Fractures of the navicular can occur in isolation but, owing
to the intimate anatomical and biomechanical relationships, are
often associated with other injuries to the neighbouring bones and
joints in the foot. As a result, they can lead to long-term morbidity
and poor function. Our aim in this study was to identify patterns
of injury in a new classification system of traumatic fractures
of the navicular, with consideration being given to the commonly associated
injuries to the midfoot. We undertook a retrospective review of 285 consecutive patients
presenting over an eight- year period with a fracture of the navicular.
Five common patterns of injury were identified and classified according
to the radiological features. Type 1 fractures are dorsal avulsion
injuries related to the capsule of the talonavicular joint. Type
2 fractures are isolated avulsion injuries to the tuberosity of
the navicular. Type 3 fractures are a variant of tarsometatarsal
fracture/dislocations creating instability of the medial ray. Type
4 fractures involve the body of the navicular with no associated
injury to the lateral column and type 5 fractures occur in conjunction
with disruption of the midtarsal joint with crushing of the medial
or lateral, or both, columns of the foot.Aims
Patients and Methods
We investigated 60 patients (89 feet) with a
mean age of 64 years (61 to 67) treated for congenital clubfoot deformity,
using standardised weight-bearing radiographs of both feet and ankles
together with a functional evaluation. Talocalcaneal and talonavicular
relationships were measured and the degree of osteo-arthritic change
in the ankle and talonavicular joints was assessed. The functional
results were evaluated using a modified Laaveg-Ponseti score. The
talocalcaneal (TC) angles in the clubfeet were significantly lower
in both anteroposterior (AP) and lateral projections than in the
unaffected feet (p <
0.001 for both views). There was significant
medial subluxation of the navicular in the clubfeet compared with
the unaffected feet (p <
0.001). Severe osteoarthritis in the
ankle joint was seen in seven feet (8%) and in the talonavicular
joint in 11 feet (12%). The functional result was excellent or good
(≥ 80 points) in 29 patients (48%), and fair or poor (<
80 points)
in 31 patients (52%). Patients who had undergone few (0 to 1) surgical
procedures had better functional outcomes than those who had undergone
two or more procedures (p <
0.001). There was a significant correlation
between the functional result and the degree of medial subluxation
of the navicular (p <
0.001, r2 = 0.164), the talocalcaneal
angle on AP projection (p <
0.02, r2 = 0.025) and extent of osteoarthritis
in the ankle joint (p <
0.001). We conclude that poor functional outcome in patients with congenital
clubfoot occurs more frequently in those with medial displacement
of the navicular, osteoarthritis of the talonavicular and ankle
joints, and a low talocalcaneal angle on the AP projection, and
in patients who have undergone two or more surgical procedures. However,
the ankle joint in these patients appeared relatively resistant
to the development of osteoarthritis.
