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Complications from knee replacement surgery

Presentation and physician action

A 68-year-old woman came to Orthopedic Surgeon A due to pain and dysfunction in both knees. On July 14, 2014, the surgeon performed a right knee replacement, and on November 24, 2014, the surgeon performed a left knee replacement. No complications were noted in either surgery.

On December 22, 2014, an x-ray of the left knee obtained during the first postoperative appointment revealed a white dot posterior to the lateral tibial joint component. The patient was noted as doing well.

On March 24, 2015, the patient returned to the surgeon with reports of soreness and stiffness in her left knee. Repeat x-rays showed the same white dot. The surgeon informed the patient that he suspected a retained metal object in the patient’s left knee.

A CT scan of the left knee revealed a 3 mm metallic object in the lateral tibial joint compartment. The CT also showed no evidence of loosening or failure of the hardware placed in the November surgery.

On April 14, 2015, the patient returned to Orthopedic Surgeon A with reports of left knee pain radiating to her foot. On April 28, an arthroscopist performed an arthroscopic retrieval of the foreign body — a screw — on referral from the surgeon. Postoperatively, the patient developed a posterior medial port cellulitis that was treated with clindamycin. On May 11, the arthroscopist performed an aspiration of the knee due to erythema and drainage.

In February 2016, the patient went to Orthopedic Surgeon B on referral from her primary care physician due to knee pain. Examination showed 3+ effusion of the left knee. The knee was warm, but without fluctuance or drainage. Her knee was noted as being stable to varus and valgus stress. Range of motion was 1-to-2 degrees less than full extension to about 100 degrees of flexion. X-rays showed the components to be well sized and well-fixed to the bone in good orientation.

Orthopedic surgeon B’s impression was mechanical complication of the left knee. The surgeon suspected some mid flexion instability despite the cruciate sacrificing design. She noted that the component design has a very low-profile box which could cause the patient to have mid flexion stability closer to 90 degrees of flexion. Orthopedic Surgeon B ordered a CT of the knee to rule out infection.

On July 18, 2016, the patient returned to Orthopedic Surgeon B. The surgeon documented her concern that the retained screw in the posterior joint capsule may have damaged either the polyethylene liner and/or the femoral component.

On July 21, Orthopedic Surgeon B took the patient to surgery for an open biopsy and revision of the left total knee arthroplasty (both components). After cultures and frozen sections were obtained and showed no evidence of infection, the revision proceeded.

The implants placed by Orthopedic Surgeon A in 2014 appeared to be well fixed, well sized, and in appropriate position and rotation. Orthopedic Surgeon B noted the knee was lacking terminal 5 degrees of extension, which she felt contributed to the patient’s pain. She also noted that the patient had a small tibial component for this particular knee system. These components were replaced.

The patient’s left knee completely healed without erythema or drainage. Her range of motion was from full extension to 120 degrees of flexion, and there was no detectable instability.


The patient filed a lawsuit against Orthopedic Surgeon A alleging:

  • failure to perform an accurate count of surgical instruments;
  • failure to notice that the retractor had a screw missing at the end of the procedure; and
  • closing the surgical field when a foreign body (screw) was embedded in it.

The medical center was also named in the lawsuit with allegations that included failure to have policies and procedures in place and/or training regarding inspection of surgical equipment and maintaining an accurate count of surgical equipment.

Legal implications

Consultants for the defense were mostly supportive of Orthopedic Surgeon A, though one consultant stated that the screw was plainly visible on the first postoperative x-ray. Another said the screw was only obvious on the film in hindsight, and that the visible “white dot” would not have caused him to believe there was a retained foreign object.

Experts for the plaintiff were more critical of Orthopedic Surgeon A for failing to notice the screw dropping out of the retractor into the surgical field, and then for closing the patient’s knee with the foreign body retained.

One of the experts stated that the failure to locate and remove the screw from the knee at the time of surgery resulted in the patient enduring aspirations of the knee; months of pain and swelling; and arthroscopic surgery to retrieve the screw.

Orthopedic Surgeon A suspected that the screw fell out of a set of retractors into the open surgical site at the end of the knee replacement surgery. He also reasoned that the retractors would have fallen apart in his hand if the screw had fallen out, but that did not happen. Since none of the nurses informed him of a missing screw, he believed he did not have a reason to look for one. There were also criticisms of the medical center’s operating room staff for failing to detect the missing and retained screw.


This case was settled on behalf of Orthopedic Surgeon A. The medical center also settled with the patient.

Risk management considerations

Manually counting all instruments and sponges at the start and end of a surgery is standard practice. However, manual counting methods are not always conclusive.

When creating, adopting, or revising written protocols for surgical counts, consider including:

  • when the counts are performed (pre-, during, and post-surgery);
  • who performs the count;
  • what materials are counted;
  • how the count is verified and documented; and
  • when protocols are reviewed and revised as appropriate.

When a count cannot be performed, an x-ray should be taken before the patient leaves the operating room, if the patient’s status permits, or as soon as possible thereafter. (1)

A surgeon can help decrease the likelihood of retained surgical instruments (RSI) by carefully examining the wound him- or herself before closure. (1) The Joint Commission recommends a “methodical wound exploration, including visual and, whenever possible, manual examination” at the opening and closing of a surgical wound. This includes “inspecting instruments for signs of breakage—before and after use—to prevent the retention of device fragments.” (2)

According to The Joint Commission, the most common causes of RSI are the absence of, or noncompliance with, policies and procedures, communication barriers, and inadequate staff education. They recommend intra-operative radiography, wound opening and closing procedures, and appropriate documentation to mitigate RSI.


1 World Health Organization. WHO Guidelines for Safe Surgery 2009: Safe Surgery Saves Lives. Available at

2. The Joint Comission. Preventing unintended retained foreign objects. Sentinel Event Alert, Issue 51, October 17, 2013. Available at