From the Guidelines
Patients with uncontrolled hyperglycemia, typically defined as having hemoglobin A1C levels above 8%, should postpone total knee replacement surgery until their blood glucose is optimized. This is based on the most recent and highest quality study, which suggests that elevated hemoglobin A1C levels are associated with poor postoperative outcomes, including increased risk of surgical site infections, poor wound healing, and prolonged hospital stays 1.
Key Considerations
- Before surgery, blood glucose should be optimized, ideally bringing fasting levels below 180 mg/dL and A1C below 8% 1.
- Close management with appropriate diabetes medications, such as oral agents like metformin or insulin therapy as needed, is necessary for at least 2-3 months before surgery.
- During the perioperative period, blood glucose should be monitored frequently, with target levels between 140-180 mg/dL.
- The decision to postpone surgery should be made on a case-by-case basis, taking into account the individual patient's unique risks and benefits, as well as the potential consequences of delaying surgery 1.
Rationale
The physiological reason for these complications involves impaired immune function, compromised microcirculation, and delayed collagen synthesis when blood glucose levels remain elevated. A retrospective study found that preoperative blood glucose levels ≥200 mg/dL were associated with a >2-fold higher all-cause mortality rate and a >4-fold cardiovascular mortality rate compared with patients with normal blood glucose levels 1.
Clinical Implications
Surgeons may postpone elective knee replacement if blood sugar control is inadequate due to the significantly higher risk of postoperative complications. However, emergent or time-sensitive procedures should not be delayed to achieve a target hemoglobin A1C; instead, the focus should be on optimizing perioperative glucose control 1.
From the Research
Contraindications to Total Knee Replacement in Patients with Hyperglycemia
- Uncontrolled high blood sugar, particularly when blood glucose levels exceed a threshold of 250 mg/dl or HbA1c levels are higher than 8.5 - 9%, is a contraindication to total knee replacement surgery, as it increases the risk of severe complications 2.
- Poor glycemic control, as indicated by elevated HbA1c levels, may be associated with adverse surgical outcomes, although the evidence is not conclusive 3, 4.
- Some studies suggest that achieving an HbA1c value of ≤7.0% may not be possible for certain diabetic patients, and such a requirement may risk access to total joint arthroplasty treatment 5.
Preoperative Glycemic Control
- Improving glycemic control prior to surgery is important to reduce the risk of postoperative complications, but the benefit of improving glycemic control must be weighed against the risks of delaying necessary elective surgery 4.
- A preoperative HbA1c goal of ≤7.0% may be difficult to achieve for some diabetic patients, and a more realistic goal may be ≤8.0% 5.