Aims. To develop and externally validate a parsimonious statistical
The influence of identifiable pre-operative factors on the outcome
of eccentric rotational acetabular osteotomy (ERAO) is unknown.
We aimed to determine the factors that might influence the outcome,
in order to develop a scoring system for predicting the prognosis
for patients undergoing this procedure. We reviewed 700 consecutive ERAOs in 54 men and 646 women with
symptomatic acetabular dysplasia or early onset osteoarthritis (OA)
of the hip, which were undertaken between September 1989 and March
2013. The patients’ pre-operative background, clinical and radiological
findings were examined retrospectively. Multivariate Cox regression
analysis was performed using the time from the day of surgery to
a conversion to total hip arthroplasty (THA) as an endpoint. A risk
score was calculated to predict the prognosis for conversion to
THA, and its predictive capacity was investigated.Aims
Patients and Methods
Peri-articular soft-tissue masses or ‘pseudotumours’
can occur after large-diameter metal-on-metal (MoM) resurfacing
of the hip and conventional total hip replacement (THR). Our aim
was to assess the incidence of pseudotumour formation and to identify
risk factors for their formation in a prospective cohort study. A total of 119 patients who underwent 120 MoM THRs with large-diameter
femoral heads between January 2005 and November 2007 were included
in the study. Outcome scores, serum metal ion levels, radiographs
and CT scans were obtained. Patients with symptoms or an identified
pseudotumour were offered MRI and an ultrasound-guided biopsy. There were 108 patients (109 hips) eligible for evaluation by
CT scan at a mean follow-up of 3.6 years (2.5 to 4.5); 42 patients
(39%) were diagnosed with a pseudotumour. The hips of 13 patients
(12%) were revised to a polyethylene acetabular component with small-diameter
metal head. Patients with elevated serum metal ion levels had a
four times increased risk of developing a pseudotumour. This study shows a substantially higher incidence of pseudotumour
formation and subsequent revisions in patients with MoM THRs than
previously reported. Because most revision cases were identified
only after an intensive screening protocol, we recommend close monitoring
of patients with MoM THR.