Patellofemoral Arthroplasty: Inlay vs. Onlay

September 1, 2015

A recent study, published in the KSSTA journal, compared two different implant types used in Patellofemoral Arthroplasty (PFA):

  • Group I consisted of an inlay (HemiCAP® Wave, Arthrosurface, Franklin, MA)
  • Group II was based on an onlay design (2nd generation, Journey™ PFJ, Smith & Nephew, Andover, MA)

snacAll patients were matched for age, gender, body mass index, and follow-up period with an independent observer evaluating the patients prospectively. Follow-up was 26 months for the inlay group and 25 months for the onlay cohort. No significant progression of tibiofemoral osteoarthritis (OA) was observed within the inlay group, whereas over half of the onlay group showed progression of knee OA (53%). While the mechanism of the disease progression was unclear, the authors hypothesized that the “onlay” device overstuffed the patellofemoral joint leading to chronic synovitis. The secretion of pro-inflammatory cytokines resulting from the synovitis is a known risk factor for OA. In addition, raising the height of the trochlea, which comes from using an onlay device, may have adverse effects on the extensor mechanism. This may increase the pressure in the femoral-tibial joint as the knee moves from extension to flexion. Based on this study, the inlay PF HemiCAP® design may improve long-term results and survival rates after isolated PFA.

Read the abstract here: http://www.ncbi.nlm.nih.gov/pubmed/26231153
Wave1

12 responses to “Patellofemoral Arthroplasty: Inlay vs. Onlay”

  1. Val says:

    What doctors in Tucson do this?

  2. Val says:

    I would like to get this done instead of knee replacement

  3. valorie says:

    Is there any one I can talk to that has had thie done in the last couple of years?

  4. Warren Schulte says:

    Would appreciate any information via mail Box 971, Lake City, CO 81235 or whs41@centurytel.net

  5. I have considerable arthritis in my joints. Are the hemicap Implants considered A partial replacement just for folks with minimal arthritis? Or can it be used as a substitute for a full joint replacement. I am very interested because I am a very active person and the full joint replacement implants that I have encountered are vulnerable to my activity.

    • arthrosurface says:

      Hi Harlan – It’s possible that you could be a candidate! The best way to know is to consult with a surgeon who is trained and uses HemiCAP products.

  6. Frank Whalen says:

    I am 52 years old and had a hemicap replacement in my left shoulder in April, 2016. Range of motion is normal, no pain and I am back to Powerlifting! I just wanted to say thank you Arthrosurface!

  7. Stacey Sickler says:

    May I please have more information about this procedure?

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