Total knee arthroplasty has evolved considerably over the last thirty years. Early implant design achieved the short-term goals of pain relief and mobility, however loosening and polyethylene wear associated with over constraint was problematic. The Low Contact Stress total knee arthroplasty was developed in an attempt to address the problems of loosening and polyethylene wear. The highly congruent interface between the femoral component and the mobile insert minimises stress within the polyethylene and reduces the potential of wear and damage. Furthermore, the mobile bearing phenomenon minimises both torsional and shear stresses at the component bone interface. In our unit the impact of choice is the LCS rotating platform prosthesis, which is inserted with cruciate-sacrifice.

We reviewed 219 patients (272 knees) with an average follow-up of 6 years (5–8 years). In almost all cases the components were inserted with cement fixation. The patella was primarily resurfaced in 20 patients (21 knees). All operations were performed or supervised by the senior author. Female to male ratio was 2:1. Average age at surgery was 68 years (40–86) with osteoarthritis being the commonest primary diagnosis (89%). Postoperative range of motion ranges from 30–130° (average 103°). Average Oxford Knee, American Knee Society Score and Patellar Score was 19 (12–53), 160 (42–199) and 25 (4–30) respectively. Six patients (1.7%) required MUA at six weeks. Two patients (0.6%) required secondary patellar resurfacing. Three patients (0.8%) had revision of their components for persistent pain. At operation all components were noted to be well fixed. Spinout of the rotating platform occurred in one patient (0.3%). This was treated by exchange of the insert.

In conclusion, our early results of the LCS rotating platform prosthesis are encouraging with no cases of component loosening to date. This supports the continued use of the implant.

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.