Hip and Knee Replacements in Canada: Distributions and Clinical Characteristics
Findings from the 2006 CJRR Annual Report

Shaheena Mukhi, Team Lead, CJRR
Mihaela Marin, Senior Analyst, CJRR
Margaret Keresteci, Manager of Clinical Registries
Canadian Institute of Health Information
Toronto, ON

October 2006 marked the release of the 2006 Canadian Joint Replacement Registry (CJRR) annual report, fifth in a series, on hip and knee replacements in Canada. National level findings included in CJRR's annual report are from the Hospital Morbidity Database (HMDB) and CJRR database, both of which are managed by the Canadian Institute for Health Information (CIHI). Clinical information for this report is obtained from 510 participating orthopaedic surgeons, working under the auspices of the Canadian Orthopaedic Association and the Canadian Orthopaedic Foundation.

Demand for Hip and Knee Replacements
National findings based on the data show that the demand for hip and knee replacements is on a steady rise in Canada. In 2004-2005, there were a total of 58,714 hip and knee replacements performed on Canadian residents; representing a 10-year increase of 87% from 31,463 procedures in 1994-1995 and a one-year increase of 9.7% from 53,517 procedures in 2003-2004 (Figure 1).

Figure 1 

Joint replacement distribution over a 10-year period shows that more knee replacement procedures were performed, relative to hip replacement procedures since 1994-1995 in Canada. In 2004-2005, there were 33,590 hospitalizations for knee and 25,124 hospitalizations for hip replacements. During the decade reported, the number of knee replacement procedures performed has more than doubled (124.8%) and there has been a 52% increase in the number of hip replacements (Figure 1).

National Look at Hip and Knee Replacements
Across the nation, provincial variations in joint replacement rates continue to be observed. Individual rates for the Territories were excluded due to reporting of small numbers, but were included in the overall national calculations.

Age standardized rates of hip replacement were highest in Prince Edward Island and Saskatchewan (86.6 and 80.7 per 100,000 population, respectively) and lowest in Newfoundland and Labrador, and Quebec (50.1 and 44.4 per 100,000 respectively) (Figure 2). 

Figure 2 

Age standardized rates of knee replacement were highest in Saskatchewan, Ontario and Prince Edward Island (120.9, 107.0 and 106.2 per 100,000 population, respectively), and lowest in Newfoundland and Labrador, and Quebec (66.7 and 55.6 per 100,000 population respectively) (Figure 2).

Patient Demographics
There were observed differences in demographics among recipients of hip and knee replacements. In 2004-2005, significantly (p<0.0001) more females than males underwent hip and knee replacements (57% for hip and 60% for knee). The highest proportions of hip and knee replacements were noted in the 65 to 74 years age group (31% for hip and 37% for knee) followed by the 75 to 84 years age group (28% for hip and 28% for knee). The lowest proportions of hip and knee replacements were noted among recipients falling in the younger than 45 and the 85 years and older age groups.

Overall, findings in the 2006 CJRR annual report show that Canadians receiving knee replacements were significantly older than those receiving hip replacements (p<0.0001) (Figure 3).

Figure 3 

Length of Hospital Stay
The 2006 CJRR annual report indicates a decline in average length of stay for hip and knee replacements since 1994-1995. Between 1994-1995 and 2004-2005, average length of stay for hip replacement decreased by 36%, from 14 to 9 days; and for knee replacement, it decreased by 42%, from 12 to 7 days (Figure 4).

Figure 4

In 2004-2005, on average, females were hospitalized for a longer duration than their male counterparts for either hip (9.2 and 7.7 days respectively) or knee (6.7 and 6.5 days respectively) replacement procedure.

Surgical and Clinical Characteristics
In 2004-2005, of the hip replacements reported, 88% were primary surgeries, while of the knee replacements reported to CJRR, 94% represented primary surgeries.

Degenerative osteoarthritis was the most common diagnosis indicated for both primary hip replacements (81%) and primary knee replacements (93%). The next most common diagnoses include osteonecrosis (6%) for hip and inflammatory arthritis (4%) for knee replacements.

For hip replacement revisions, the leading reason was attributed to aseptic loosening (54%), followed by osteolysis (28%), poly wear, and instability (16%). For knee replacement revisions, the most common reason was also aseptic loosening (35%), followed by poly wear (30%), osteolysis (18%) and instability (13%) (Figure 5). 

Figure 5

Visit www.cihi.ca/cjrr for an in-depth view of the reported analysis, found in this article. Please visit the CJRR web site www.cihi.ca/cjrr or contact us at Cet e-mail est protégé contre les robots collecteurs de mails, votre navigateur doit accepter le Javascript pour le voir to access CJRR annual reports, to provide feedback or to join CJRR. Participation of orthopaedic surgeons is recognized as instrumental in CJRR and is encouraged.

CIHI is committed to providing comprehensive, accurate and comparable information in a timely manner. 

References
Canadian Institute for Health Information (CIHI). Canadian joint Replacement Registry (CJRR), 2006 Report. Hip and Knee Replacements in Canada. (Toronto: CIHI 2006).