Introduction: THR and TKR have been shown to be successful treatments for moderate to severe osteoarthritis of the hip and knee. The requirement for total joint replacement will increase as the population ages. This study reports on the incidence of THR and TKR in an Australian population.

Method: Age and gender specific numbers of THR and TKR for the Australian population, 1994–1998 were obtained from the Australian Institute of Health and Welfare. The same data for South Australia, 1988–1998 were obtained from the Department of Human Services Epidemiology Branch. The incidences were calculated and tested for changes over time.

Results: For the Australian population in 1994 there were 9,120 THR and by 1998 this had increased by 25.9% to 11,488 THR. There were 10,132 TKR in 1994 and by 1998 this had increased by 42.8% to 14,472 TKR. Stratified by age group changes in incidence rate with respect to time was statistically tested using regression analysis. For the eleven year data from South Australia there was a significant increase in the overall incidence of THR (p=0.012). There were significant increases in TKR incidence, although this increase was not uniform across all age groups (p< 0.001). The increase in TKR incidence was greater than that for THR. For both THR and TKR there were no significant differences on the basis of gender.

Conclusion: The incidence of THR is increasing in Australia and TKR incidence is increasing at a greater rate. Future projections must take into account these changing incidences as well as changes in population demographics.

We report a prospective randomly controlled trial to examine the effectiveness of continuous passive motion (CPM) in improving postoperative function and range of movement after total knee arthroplasty (TKA).

We allocated 53 patients (57 knees) to one of three postoperative regimes: no CPM (n = 19); CPM at 0 to 40° (0 to 40 CPM; n = 18); and CPM at 0 to 70° (0 to 70 CPM; n = 20). Those in the CPM groups had CPM for 48 hours and all patients had an identical regime of physiotherapy. There was an even distribution of various cemented and cementless TKAs in each group. Patients were assessed preoperatively and at one week and at one year postoperatively.

At one week, there was a statistically significant increase in the range of flexion and total range of movement in the 0 to 70 CPM group compared with the no-CPM group. At one year we found no significant differences in mean flexion, overall range of movement, fixed flexion deformity or functional results in the three groups. Those who had CPM had a significant increase in analgesic requirement (p = 0.04). There was an increased mean blood drainage postoperatively in those who had 0 to 70 CPM (1558 ml) compared with those with no CPM (956 ml) (t = 2.96, p = 0.005) and with 0 to 40 CPM (1017 ml) (t = 2.62, p = 0.01).

Our findings show that CPM had no significant advantage in terms of improving function or range of movement, and that its use increased blood loss and analgesic requirements.