Correct Knee, Wrong Implant

I showed the surgeon the implant boxes, who confirmed they were the correct ones. The boxes were then opened and handed to the scrub nurse. Shortly after the cement had set, the knee in question didn’t look right. It was a right implant in a left knee. Informed surgeon that the implant was wrong. Surgeon attempted to remove the femoral component and a small piece of the femoral condyle came away that was cemented to the femoral component. At this point, three other surgeons scrubbed to assist. They proceeded to remove the femoral component and then repaired the left lateral condyle which had broken off. Once the condyle was repaired, it was decided that a total stabilizer femoral component normally used for revisions of prior knee replacements would be required.

Patient was scheduled and consented for a left total knee arthroplasty. A right femoral component was placed instead of the correct left femoral component. This was discovered on x-ray in PACU. Patient was allowed to wake up and physician discussed risks and benefits of leaving the left component in place or returning to surgery to have the right-side component placed. The patient elected to return to surgery and have the implant replaced. The patient recovered well from the two procedures and discharged home the following day.

Bilateral case. The left knee was opened first. The scrub tech opened the right implants instead of the left implants. The nurse and surgeon both inspected the right implants and implanted them. While the left knee was beginning to be closed, the nurse looked at the implant ticket and noticed that the right implants were put in instead of the left. The surgeon immediately explanted the right implants and implanted the left implants and closed the knee. He then implanted a new set of right implants in the right knee without a problem. This added 1 hour to the case.

Knee replacements pose a significant risk of wrong-sided implant use. Many CHPSO members reported experiencing near misses. And, several times, a wrong-sided component was implanted. Review of the FDA MAUDE device event reporting database shows even more cases, and the case summaries above were selected from there.

Insertion of the wrong medical implant into the correct surgical site is a serious reportable event according the National Quality Forum: Wrong surgical or other invasive procedure performed on a patient.

CHPSO’s analysis identified several factors leading to the increased risk, including:

  1. Hospitals have protocols in place for confirming procedure sidedness before starting the procedure. Picking the correct implant to use in the case may happen much later.
  2. Hip components are typically bilateral without need to identify sidedness, while many knee components are sided. Procedures that work well for confirming proper hip components are not sufficient for knee components.
  3. Operating room personnel may not always follow a standardized process for knee implant verification.
  4. Knee components that are sided are often subtly asymmetric, and may not appear obviously wrong when inserted incorrectly.
  5. Package labeling for side is not standardized, may be remote from the size label and may not be as prominently displayed.
  6. Sizing is a key step in the procedure and much attention is paid to proper size as opposed to proper side, drawing attention away from the sidedness labeling.
  7. Several people including supplier representatives may move stock around. Unless well-controlled, this could lead to devices being in unexpected locations.
  8. Bilateral procedures are not uncommon. Devices for both sides may be present in the OR simultaneously and there are multiple times during bilateral procedures at which sidedness errors can occur.


Hospitals have diverse ways of managing stock, OR staffing, vendor representatives and OR processes. Consequently, the following recommendations need to be evaluated in the local context for applicability.

  1. Review the standard processes for implant verification and confirm that standard processes are uniformly followed.
  2. Review how component stock is managed, including who can move, remove and replace items. Standardize how separation by laterality is managed.
  3. Identify a proper point in the procedure to definitively verify sidedness of the components. Some organizations may do this during the initial time out by verifying that the only components in the room are for the correct side; not allowing in any other components without a repeat time out. Others may implement this at the time of implant sizing and specific component selection.
  4. Review how vendor representatives are involved in picking the correct component box.
  5. Consider providing memory aids (e.g., pictures) pointing out the locations of the size and side information on the range of devices used in that facility, and showing which devices are sided and which are bilateral.

If you have documents, e.g., policies or safety alerts, that you wish to share on this topic, please contact Rory Jaffe at 916-552-2600 or We can deidentify the documents if you prefer.


National Quality Forum (NQF),Serious Reportable Events in Healthcare—2011 Update: A Consensus Report, Washington, DC: NQF; 2011.