Abstract
Rapidly progressive cases of primary idiopathic hip osteoarthrosis are well known and recognised. The prevalence reported in the literature varies from 4–18%. Three types have been identified- type 1 (rapid), type 2 (moderate) and type 3 (delayed) depending on the duration of chondrolysis and the subsequent rate of bone loss per year.
We reviewed the charts of all patients deemed to be RPO type 1 who had underwent hip arthroplasty under the care of the senior author (DEB) over a two-year period in an attempt to identify risk factors, which may have contributed to the rapid progression of their disease. All patients were treated using a custom femoral stem and a spiked Duraloc cementless socket following careful preparation of the acetabulum.
We identified 34 patients (40 hips) with type 1 rapidly progressive osteoarthrosis. Over the same time period 991 patients had underwent primary total hip arthroplasty, giving a prevalence of 4%. Of the 34 patients, 29 were female of average age 70.6 years (range, 51–83 years). All of the bilateral cases (6 patients) were female. Body mass index (BMI) for the female group ranged from 20.6 to 41.1Kg/m2 (average, 28.2kg/m2) whilst that for the males was on average 25.8Kg/m2 (range, 23.4–29.7Kg/m2).
Preoperative erythrocyte sedimentation rate (ESR) was 18mm/hr on average for the female group (range, 2–65mm/hr) and ranged from 3–52mm/hr (average, 20mm/hr) for the male patients. The preoperative Oxford Hip Score averaged 51 points for the female group and 48 points for the male group.
A detailed review of occupational history did not reveal any common occupational hazard. The majority of patients were non-smokers and denied any regular alcohol intake. Twenty-two patients (65%) had a history of hypertension. Twenty-seven patients (79%) had a history of non-steroidal anti-inflammatory use (most common preparation-diclofenac). Twenty-four patients (71%) resided in a rural area.
When compared to a cohort of patients undergoing primary total hip arthroplasty over the same time period, the only statistically significant risk factor identified was female gender.
We conclude, that patients who develop rapidly progressive osteoarthrosis of the hip are difficult to identify due to the absence of specific clinical features. We also outline our experience in the management of these technically challenging cases.
These abstracts were prepared by Mr Peter Kay. Correspondence should be addressed to him at The Hip Centre, Wrightington Hospital, Appley Bridge, Wigan, Lancashire WN6 9EP.
