Meniscal Dimensions Research Articles

Meniscal Allograft Size Can Be Predicted by Height, Weight, and Gender

Our purpose was to determine if height, weight, and gender can be used to accurately predict proper meniscal allograft dimensions. Data were obtained from the Joint Restoration Foundation (AlloSource, Centennial, CO) regarding meniscal size and patient characteristics from meniscal donors. Donor height, weight, sex, age, and anatomic meniscal dimensions were recorded for 930 donor menisci in 664 patients. Multivariate regressions were completed using gender, height, and weight as independent variables and lateral meniscus length, lateral meniscus width, medial meniscus length, and medial meniscus width as dependent variables. The regression formulas were then reapplied to the data in order to produce estimated meniscus dimensions based on donor height, weight, and gender. A 90:10 split of the data was used to validate the regression models. Predicted meniscal size was then compared to actual meniscal size and the results compared to current measurement techniques. Regression formulas showed the ability to predict meniscal size based on gender, height, and weight with standard deviations (SDs) equal to or less than current radiographic techniques (SD, 6.4% to 8.2%). Average differences between predicted size and actual size ranged from 5.2% to 6.5% for length and 5.2% to 6.0% for width. Patient height was found to be a much more powerful predictor of meniscal size than patient weight. Data from the 90:10 split of data validated the model on an independent sample. These validated outputs were then compared to contemporary techniques and found to have lower SDs and average error rates in the majority of cases. We have proposed a validated regression model that uses height, weight, and gender variables to accurately predict required allograft meniscal size. We compared it against previously published data for radiographic and magnetic resonance imaging sizing techniques and found it to produce results that were, overall, slightly more accurate. This model provides a novel method for sizing meniscal allografts.

Meniscal Sizing Based on Gender, Height, and Weight

Successful meniscus transplantation may depend on accurate sizing. Meniscal sizing is currently determined by measuring a combination of bony landmarks and soft-tissue insertion points through images obtained radiographically or by magnetic resonance imaging (MRI). The literature widely reports inaccuracy in sizing resulting from radiographic errors in magnification, erroneous identification of bony landmarks, and difficulty in differentiating between the soft-tissue and bone interface. In our meniscus transplantations we have observed that when the height and weight of the recipient matched those of the donor, the meniscal size appeared to be a match at surgical implantation; we designed this study to confirm this observation. The MRI-based meniscal sizing of 111 patients (63 male and 38 female patients; mean age, 44 years [range, 15 to 76 years]), totaling 147 menisci (87 lateral and 60 medial), was compared with the height, weight, gender, and body mass index (BMI) of each patient. MRI scans were obtained with a 1.0-Tesla MRI system (ONI Medical Systems, Wilmington, MA). Sizing was performed by an independent musculoskeletal MRI radiologist as established by the literature. Statistical methods include nonparametric Pearson correlation (r) between MRI-based lateral meniscal width, lateral meniscal length, medial meniscal width, medial meniscal length, total tibial plateau width, and patient height, weight, gender, and BMI. Significance at the P = .05 level was used. Height was found to have a linear relationship to total tibial plateau, which has a good predictive correlation with meniscal dimensions of r > 0.7. Female patients generally present with smaller dimensions than male patients. High-BMI groups present with significantly larger meniscal dimensions than low-BMI groups at any given height. Height, weight, and gender are easily obtained variables and are proportional to meniscal tissue dimensions. These exploratory statistics establish correlations between height, weight, gender, total tibial plateau width, and meniscal size. Height, weight, and gender should be considered by both tissue banks and surgeons as fast and cost-effective variables by which to predict meniscal dimensions.

Dehydration rates of meniscus and articular cartilage in vitro using a fast and accurate laser-based coordinate digitizing system

When used in in vitro studies, soft tissues such as the meniscus and articular cartilage are susceptible to dehydration and its effects, such as changes in size and shape as well as changes in structural and material properties. To quantify the effect of dehydration on the meniscus and articular cartilage, the first two objectives of this study were to (1) determine the percent change in meniscal dimensions over time due to dehydration, and (2) determine the percent change in articular cartilage thickness due to dehydration. To satisfy these two objectives, the third objective was to develop a new laser-based three-dimensional coordinate digitizing system (3-DCDS II) that can scan either the meniscus or articular cartilage surface within a time such that there is less than a 5% change in measurements due to dehydration. The new instrument was used to measure changes in meniscal and articular cartilage dimensions of six cadaveric specimens, which were exposed to air for 120 and 130 min, respectively. While there was no change in meniscal width, meniscal height decreased linearly by 4.5% per hour. Articular cartilage thickness decreased nonlinearly at a rate of 6% per hour after 10 min, and at a rate of 16% per hour after 130 min. The system bias and precision of the new instrument at 0° slope of the surface being scanned were 0.0 and 2.6 μ m , respectively, while at 45° slope the bias and precision were 31.1 and 22.6 μ m , respectively. The resolution ranged between 200 and 500 μ m . Scanning an area of 60 × 80 mm (approximately the depth and width of a human tibial plateau) took 8 min and a complete scan of all five sides of a meniscus took 24 min. Thus, the 3-DCDS II can scan an entire meniscus with less than 2% change in dimensions due to dehydration and articular cartilage with less than 0.4% change. This study provides new information on the amount of time that meniscal tissue and articular cartilage can be exposed to air before marked changes in size and shape, and possibly biomechanical, structural and material properties, occur. The new 3-DCDS II designed for this study provides fast and accurate dimensional measurements of both soft and hard tissues.

An anatomical study of meniscal allograft sizing.

Meniscus-to-femoral condyle congruity is essential for the development of circumferential hoop stresses and thus function of the meniscus. When meniscal allograft transplantation is performed using bony anchorage of the insertional ligaments, accurate graft-to-host size matching is therefore essential. The standard method currently employed for size matching of meniscal allografts is to rely on plain radiographs of the host's knee, from which expected meniscal dimensions are measured. This study aimed to examine the correlation between tibial plateau dimensions and meniscal dimensions. We studied 44 donor tibial plateaus with medial and lateral meniscal allografts attached intact. Meniscal and tibial plateau dimensions were measured. Linear regression analysis was used to calculate expected meniscal dimensions from each specimen's plateau dimensions. Using specific medial and lateral tibial plateau width and length measurements, meniscal dimensions could be predicted with a mean error of only 5.0+/-6.4%. When predicting meniscal dimensions from only total bony plateau width, the mean error observed was 6.2+/-8.0%. The difference between the two methods was not statistically significant. The results suggest that meniscal dimensions can be predicted accurately from tibial plateau measurements, with only small mean errors. However, potential size mismatches should be carefully borne in mind by surgeons using meniscal allografts.