hta_ knee intro.qxp - Ministero della Salute

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Since the characteristics of patients receiving a prosthesis are unlikely to be homogeneous,
the stratification of performance data per group of patients is important to allow comparisons
across registers. For example, gender, age, and indication for procedure should be reported. As
stated in our previous HTA report on the prostheses for total hip replacement 23 we believe that,
the performance of each knee system (clearly identified by system name and manufacturer)
should be expressed with stratification by sex, age groups and indication, to allow a more efficient
analysis. All these variables affect the implant-related outcome 36,37 .
We attempted to overcome heterogeneity of data to compare data-sets from each register. We
corresponded with key persons from the 11 registers identified (reported in Table 7.1) to obtain further
data related to the last published report. Data requests were made by e-mail, introducing the
Agenas and explaining the HTA report’s objectives. The recipients were informed that the project
was commissioned and financed by the Italian MLHSP. Results are shown in the next paragraph.
7.3.2 Implants performance from arthroplasty registers
Replies obtained from our data requests were various and are synthesised in Table 7.4. We
received all data requested from 3 out of the 11 registers contacted: Australia, Emilia-Romagna,
and New Zealand. We further asked for additional stratification by age (patients aged 50 and
over). Only Australia and Emilia-Romagna sent us the additional data and thus we were forced to
exclude the New Zealand register because of the absence of sufficient age breakdown. This reduced
our sources to 2 registers.
From the data obtained we were able to collect, for each implant model, the following variables:
• Implant name (model name and manufacturer);
• Total number of procedures performed with the implant;
• Percent of females and males who received the implant;
• Mean age (and range) of the population that received the implant;
• Percent of procedures performed for OA;
• Revision rate at 3 and 5 years of follow-up.
These data are presented for Australia (Tables 7.5-7.7), Emilia-Romagna (Table 7.8), and New
Zealand (Table 7.9 and 7.10) respectively.
TKR appeared most commonly performed in females than in males and the rate of OA as primary
indication appeared to be around 90% (this seems verified in all three registers except in
Emilia-Romagna where this seems slightly lower). The mean age for primary TKR was over 60
years for all the three registers. Moreover, the 10 most used knee systems cover more than 70%
of the total number of observations in each register and several of these seem to be among the
most frequently used implants in all the registers (for cemented, uncemented and hybrid fixation).