Adverse reaction to wear and corrosion debris
is a cause for concern in total hip arthroplasty (THA). Modular junctions
are a potential source of such wear products and are associated
with secondary pseudotumour formation. We present a consecutive series of 17 patients treated at our
unit for this complication following metal-on-highly cross-linked
polyethylene (MoP) THA. We emphasise the risk of misdiagnosis as
infection, and present the aggregate laboratory results and pathological
findings in this series. The clinical presentation was pain, swelling or instability.
Solid, cystic and mixed soft-tissue lesions were noted on imaging
and confirmed intra-operatively. Corrosion at the head–neck junction
was noted in all cases. No bacteria were isolated on multiple pre-
and intra-operative samples yet the mean erythrocyte sedimentation
rate was 49 (9 to 100) and C-reactive protein 32 (0.6 to 106) and
stromal polymorphonuclear cell counts were noted in nine cases. Adverse soft–tissue reactions can occur in MoP THA owing to corrosion
products released from the head–neck junction. The diagnosis should
be carefully considered when investigating pain after THA. This
may avoid the misdiagnosis of periprosthetic infection with an unidentified
organism and mitigate the unnecessary management of these cases
with complete single- or two-stage exchange. Cite this article:
We report 17 patients (20 hips) in whom metal-on-metal resurfacing had been performed and who presented with various symptoms and a soft-tissue mass which we termed a pseudotumour. Each patient underwent plain radiography and in some, CT, MRI and ultrasonography were also performed. In addition, histological examination of available samples was undertaken. All the patients were women and their presentation was variable. The most common symptom was discomfort in the region of the hip. Other symptoms included spontaneous dislocation, nerve palsy, a noticeable mass or a rash. The common histological features were extensive necrosis and lymphocytic infiltration. To date, 13 of the 20 hips have required revision to a conventional hip replacement. Two are awaiting revision. We estimate that approximately 1% of patients who have a metal-on-metal resurfacing develop a pseudotumour within five years. The cause is unknown and is probably multifactorial. There may be a toxic reaction to an excess of particulate metal wear debris or a hypersensitivity reaction to a normal amount of metal debris. We are concerned that with time the incidence of these pseudotumours may increase. Further investigation is required to define their cause.
The systemic use of steroids and habitual alcohol
intake are two major causative factors in the development of idiopathic
osteonecrosis of the femoral head (ONFH). To examine any interaction
between oral corticosteroid use and alcohol intake on the risk of
ONFH, we conducted a hospital-based case-control study of 71 cases
with ONFH (mean age 45 years (20 to 79)) and 227 matched controls
(mean age 47 years (18 to 79)). Alcohol intake was positively associated
with ONFH among all subjects: the adjusted odds ratio (OR) of subjects
with ≥ 3032 drink-years was 3.93 (95% confidence interval (CI) 1.18
to 13.1) compared with never-drinkers. When stratified by steroid use,
the OR of such drinkers was 11.1 (95% CI 1.30 to 95.5) among those
who had never used steroids, but 1.10 (95% CI 0.21 to 4.79) among
those who had. When we assessed any interaction based on a two-by-two
table of alcohol and steroid use, the OR of those non-drinkers who
did use steroids was markedly elevated (OR 31.5) compared with users
of neither. However, no further increase in OR was noted for the
effect of using both (OR 31.6). We detected neither a multiplicative
nor an additive interaction (p for multiplicative interaction 0.19;
synergy index 0.95), suggesting that the added effect of alcohol
may be trivial compared with the overwhelming effect of steroids
in the development of ONFH. Cite this article:
We measured the plasma 25-hydroxyvitamin D3 (25(OH)D3) levels in 62 consecutive Caucasian patients undergoing total hip replacement for osteoarthritis. The patients were divided into two groups based on whether they were vitamin D sufficient or deficient. The groups were matched for age, gender and the American Society of Anaesthesiologists (ASA) grade. The prevalence of vitamin D deficiency in our patients was comparable with recent population-based studies performed in the United Kingdom. Patients with vitamin D deficiency had lower pre-operative Harris hip scores (Mann-Whitney test, p = 0.018) and were significantly less likely to attain an excellent outcome from total hip replacement (chi-squared test, p = 0.038). Vitamin D levels were found to positively correlate with both pre- and post-operative Harris hip scores. These results warrant further study of vitamin D deficiency in patients undergoing joint replacement as it is a risk factor for a suboptimal outcome which is relatively simple and cheap to correct.
