How long does a knee replacement last?

23rd February 2019, Dr Chee L Khoo

Joint replacement is the mainstay treatment for advanced arthritis. Unfortunately, almost all joint replacements fail over time. We are frequently asked by patients “how long does the replacement last?”. It’s important to know how long a joint is supposed to last because it determines the “ideal” age to have the first knee replacement. Further, we can anticipate when symptoms will be coming up and start exploring the feasibility of the next joint replacement. So, how long does a knee replacement really last before a revision is necessary?

The younger the patient is, the earlier the joint replacement fails and they older the patient is, the longer the joint replacements last.. We were taught that on average, a knee replacement will last 10-15 years before aseptic loosening causes pain and disability and a joint revision is on the cards. A previous analysis of the Finnish Arthroplasty Registry provided an estimate of the survival of total knee replacement at 15 years of 88·7% for total knee replacement (TKR) and 69·6% for unicondylar knee replacement (UKR) (1). An analysis that used the UK Clinical Practice Research Datalink (CPRD) database was published in 2017, and estimated survival of TKR to be 89·7% at 20 years (2).

A recent systematic review and meta-analysis reviewed articles reporting 15 years or longer survival of primary total knee replacement, unicondylar knee replacement and patellofemoral replacement. Articles that reviewed complex primary surgeries or revisions were excluded. 26 unique case series reported survival for 6490 TKRs, with follow-up ranging from 15 years to 23 years. Fourteen case series reported prosthesis survival at 15 years (4137 TKRs) and five at 20 years (763 TKRs). Pooled analysis of data derived from case series reported at exactly 15 years or 20 years showed an all-cause construct prosthesis survivorship of 96·3% at 15 years and 94·8% at 20 years.

They also looked at national joint replacement registry reports from Australia, Denmark, Finland, New Zealand, Norway, and Sweden. The search yielded 47 series reporting TKRs and five reporting UKRs. The estimates from these series all originated from the Australian and Finnish registries. The other four arthroplasty registries did not have prosthesis survival estimates that were broken down by implant type. The pooled survival data derived from registry data showed an all-cause construct prosthesis survivorship of 76·5% at 15 years, 71·6% at 20 years, and 69·8% at 25 years.

Case series appear to have better prosthesis survivorship figures. It is not unexpected as there is likely selection and reporting bias. Looking at prosthesis survival reports this way does not necessarily account for the prosthesis survivorship of the prosthesis. Surgeon factors and patient factors may affect the decision to revise the knee replacement or not. The threshold for a revision also differs between countries.  Despite these limitations, the findings in this study are of use when patients ask us about their TKRs.

I must say that I don’t see those sort of numbers in my practice.

Access this abstract here.

References

  1. Niinimaki T, Eskelinen A, Makela K, Ohtonen P, Puhto A-P, Remes V. Unicompartmental knee arthroplasty survivorship is lower than TKA survivorship: a 27-year Finnish registry study. Clin Orthop Relat Res 2014; 472: 1496–501.
  2. Bayliss LE, Culliford D, Monk AP, et al. The effect of patient age at intervention on risk of implant revision after total replacement of the hip or knee: a population-based cohort study. Lancet 2017; 389: 1424–30.
  3. Jonathan T Evans, Robert W Walker, Jonathan P Evans, Ashley W Blom, Adrian Sayers, Michael R Whitehouse. How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet 2019; 393: 655–63