Review Question - QID 219584

This 64-year-old demonstrates a chronically draining wound following left total knee arthroplasty. The purpose of obtaining total lymphocyte counts and serum prealbumin levels is to assess for malnutrition (Answer 1).

Delayed healing/chronic wounds following total knee arthroplasty are common and often related to underlying patient-related factors. As such, a thorough history, examination, and workup are required to identify any potential causes, which often includes screening for diabetes or vascular disease, identifying the presence of tobacco use, as well as malnutrition. Malnutrition can be assessed through several serological markers, including total lymphocyte count, albumin, prealbumin, and transferrin. Several studies have demonstrated the utility of these markers in identifying malnutrition and correlated them with increased risk for wound complications and/or infection following their total joint replacement. As such, identifying and correcting malnutrition is of paramount importance to mitigate the risk of postoperative morbidity.

Cross et al. performed a review examining the presence of malnutrition in those undergoing elective orthopedic procedures, noting its high prevalence among the population. The authors investigated the risk factors associated with surgical site infections, which included obesity and diabetes as commonly associated conditions. Various laboratory markers, namely total lymphocyte count, albumin, prealbumin, and transferrin, have all demonstrated their ability as markers for nutrition. The authors ultimately emphasize the importance of preoperative optimization and particular glucose control, normalization of serum albumin, and weight loss to mitigate the risk of complications such as infection.

Morey et al. performed a retrospective review of 3,169 total knee arthroplasties investigating the efficacy of serum albumin and total lymphocyte counts as markers for malnutrition as defined by either serum albumin level <3.5 g/dL "or" a serum TLC <1500 cells/mm3 versus serum albumin <3.5 g/dL "and" TLC <1500/mm3. The authors noted a 21% malnutrition rate with the former definition, which dropped to 1.6% when the latter definition was used. Despite the small overlap of the two parameters, no differences were observed between the groups in terms of function and wound complication incidence.

Roche et al. utilized a private database to identify all total knee arthroplasty patients (n=161,625) and those who sustained postoperative wound complications (n=11,047). The authors then stratified them by using albumin prealbumin, transferrin levels as indicators of nutritional status to determine postoperative infections, wound complications, and concomitant infection with wound complications. Albumin of less than 3.5 g/dL, prealbumin of less than 15 mg/dL, and transferrin <200 mg/dL increased the risk for postoperative complications. The authors conclude assessing and normalizing these values prior to intervention is crucial in avoiding postoperative complications.

Figure A demonstrates a wound at the distal-most aspect of a previous incision for a total knee arthroplasty.

Incorrect answers:
Answers 2 and 4: ESR and CRP are useful for detecting inflammation and ruling out infection.
Answer 3: assessment of immunological status is best achieved through analysis of complement or immunoglobulin profiles
Answer 5: hematocrit, hemoglobin, and RBC counts are the most appropriate tests to assess for anemia.