Several factors have been implicated in unsatisfactory
results after total hip replacement (THR). We examined whether femoral
offset, as measured on digitised post-operative radiographs, was
associated with pain after THR. The routine post-operative radiographs
of 362 patients (230 women and 132 men, mean age 70.0 years (35.2
to 90.5)) who received primary unilateral THRs of varying designs
were measured after calibration. The femoral offset was calculated
using the known dimensions of the implants to control for femoral
rotation. Femoral offset was categorised into three groups: normal
offset (within 5 mm of the height-adjusted femoral offset), low
offset and high offset. We determined the associations to the absolute
final score and the improvement in the mean Western Ontario and
McMaster Universities osteoarthritis index (WOMAC) pain subscale
scores at three, six, 12 and 24 months, adjusting for confounding
variables. The amount of femoral offset was associated with the mean WOMAC
pain subscale score at all points of follow-up, with the low-offset
group reporting less WOMAC pain than the normal or high-offset groups
(six months: 7.01 ( Cite this article:
We investigated whether an asymmetric extension
gap seen on routine post-operative radiographs after primary total
knee replacement (TKR) is associated with pain at three, six, 12
and 24 months’ follow-up. On radiographs of 277 patients after primary
TKR we measured the distance between the tibial tray and the femoral
condyle on both the medial and lateral sides. A difference was defined
as an asymmetric extension gap. We considered three groups (no asymmetric
gap, medial-opening and lateral-opening gap) and calculated the
associations with the Western Ontario and McMaster Universities
osteoarthritis index pain scores over time. Those with an asymmetric extension gap of ≥ 1.5 mm had a significant
association with pain scores at three months’ follow-up; patients
with a medial-opening extension gap reported more pain and patients
with a lateral-opening extension gap reported less pain (p = 0.036).
This effect was still significant at six months (p = 0.044), but had
lost significance by 12 months (p = 0.924). When adjusting for multiple
cofounders the improvement in pain was more pronounced in patients
with a lateral-opening extension gap than in those with a medial-opening extension
gap at three (p = 0.037) and six months’ (p = 0.027) follow-up. Cite this article:
Although the Western Ontario and McMaster Universities
(WOMAC) osteoarthritis index was originally developed for the assessment
of non-operative treatment, it is commonly used to evaluate patients
undergoing either total hip (THR) or total knee replacement (TKR).
We assessed the importance of the 17 WOMAC function items from the perspective
of 1198 patients who underwent either THR (n = 704) or TKR (n =
494) in order to develop joint-specific short forms. After these
patients were administered the WOMAC pre-operatively and at three,
six, 12 and 24 months’ follow-up, they were asked to nominate an
item of the function scale that was most important to them. The
items chosen were significantly different between patients undergoing
THR and those undergoing TKR (p <
0.001), and there was a shift
in the priorities after surgery in both groups. Setting a threshold
for prioritised items of ≥ 5% across all follow-up, eight items
were selected for THR and seven for TKR, of which six items were
common to both. The items comprising specific WOMAC-THR and TKR
function short forms were found to be equally responsive compared
with the original WOMAC function form. Cite this article:
