Fractures of the shaft of the tibia often heal with some angulation.
Although there is biomechanical evidence that such angulation alters
load transmission through the joints of the lower limb, it is not
clear whether it can eventually lead to osteoarthritis.
One hundred and sixty-four individuals who had sustained a tibial
shaft fracture were assessed in a research clinic thirty to forty-three
years after the injury. The subjects were evaluated with regard
to self-reported lower limb joint pain, stiffness, and disability
(assessed with the Western Ontario and McMaster Universities [WOMAC]
osteoarthritis questionnaire); clinical signs of osteoarthritis;
and radiographic evidence of osteophytes and joint-space narrowing
in the knees, ankles, and subtalar joints.
Twenty-two (15%) of the 151 subjects who reported no other knee
injury reported at least moderate knee pain, and eight (6%) of the
145 subjects who reported no other ankle injury reported at least
moderate ankle pain. Seventeen (13%) of the 135 subjects who reported
no other knee or ankle injury reported at least moderate disability.
The ipsilateral side demonstrated a higher prevalence than the contralateral
side in terms of pain with passive ankle movement (nineteen versus nine
subjects, p = 0.02), pain with passive subtalar movement (fifteen
versus four subjects, p = 0.01), and radiographic signs of ankle
joint space narrowing (twelve subjects versus one subject, p = 0.0055).
Knee osteoarthritis was frequently bilateral. Forty-seven fractures
(29%) healed with coronal angulation of =5°. Apart
from an association between shortening of =10 mm and self-reported
knee pain (p = 0.016), there were no significant univariate associations between
these malunions and the development of osteoarthritis. Seventeen
(15%) of 114 eligible subjects had overall malalignment of the lower
limb, defined as a hip-knee-ankle angle outside the normal range
of 6.25° of varus to 4.75° of valgus. This malalignment
was due to the fracture malunion in nine subjects and predated the
fracture in eight. In limbs with varus or valgus malalignment, there
was an excess of subtalar stiffness (p = 0.04) and a nonsignificant trend
toward more frequent knee pain. In limbs with varus malalignment,
there was a nonsignificant trend toward more frequent radiographic
evidence of osteoarthritis in the medial compartment of the knee
joint. Most of the subjects in whom osteoarthritis was observed
had normal overall alignment of the lower limb.
The thirty-year outcome after a tibial shaft fracture is usually good,
although mild osteoarthritis is common. Fracture malunion is not
the cause of the higher prevalence of symptomatic ankle and subtalar
osteoarthritis on the side of the fracture. Although varus malalignment
of the lower limb occurs occasionally and may cause osteoarthritis
in the medial compartment of the knee, other factors are more important
in causing osteoarthritis after a tibial shaft fracture.