Importance of Independent Measurement of Width and Length of Lateral Meniscus During Preoperative Sizing for Meniscal Allograft Transplantation

Background: Successful meniscus transplantation depends on an accurate sizing of the meniscal allograft. Although accurate sizing of the meniscal allograft is crucial during meniscus transplantation, the accuracy of meniscal measurement methods is still in debate. Purpose: This study was undertaken to evaluate the relationship between the width and length of the lateral meniscus. These anatomic dimensions were also evaluated in the context of the patient's height, weight, gender, and body mass index (BMI). Study Design: Descriptive laboratory study. Methods: Ninety-one samples of fresh lateral meniscus were obtained during total knee arthroplasty. The samples were obtained carefully without injuring the meniscus itself and the bony attachment sites. For each lateral meniscus, the anatomic dimensions (width [LMW] and length [LML]) were recorded. The height, weight, gender, and BMI of the patients were also recorded. The Pearson correlation and multivariate and linear regression analysis were applied for each variable. The accuracy was defined as those measures that fell within 10% of the original size. A P value <= .05 was considered significant. Results: The mean LMW was 30.7 mm (standard deviation [SD] = 3.5) and 27.0 mm (SD = 2.6) for men and women, respectively. The mean LML was 33.7 mm (SD = 4.3) and 30.8 mm (SD = 2.6) for men and women, respectively. Thirty-nine samples (42.5%) showed LMW measurements within a 10% difference of LML, whereas 50 samples (55%) showed an LMW greater than a 10% difference of LML. Although there were correlations between LML with LMW in men and correlations between weight and LMW with LML in women, the accuracy for the derived linear regression formulas was 3%, 9%, and 12%, respectively. Conclusion: The length cannot be predicted accurately from the width of the lateral meniscus. The height, weight, gender, and BMI failed to estimate the dimensions of the lateral meniscus. Therefore, it is essential to measure the width and length separately and match it with the allograft with other size measuring methods. Clinical Relevance: This study emphasizes the importance of measuring the width and length of the lateral meniscus independently during preoperative sizing for a meniscal allograft transplantation procedure. The height, weight, gender, and body mass index may not be reliable parameters for estimating the size of the meniscus.