A New Method of Measuring the Cross-Sectional Area of Connective Tissue Structures

Abstract

There appears to be no generally accepted method of measuring in-situ the cross-sectional area of connective tissues, particularly small ones, before mechanical testing. An instrument has therefore been devised to measure the cross-sectional area of one such tissue, the rabbit medial collateral ligament, directly and nondestructively. However, the methodology is general and could be applied to other tissues with appropriate changes in detail. The concept employed in the instrument is to measure the thickness of the tissue as a function of position along the width of the tissue. The plot obtained of thickness versus width position is integrated to provide the cross-sectional area. This area is accurate to within 5 percent, depending mainly on alignment of the instrument and pre-load of the ligament. Results on the mid-substance of the rabbit medial collateral ligaments are repeatable and reproducible. Values of maximum width and thickness are less variable than those obtained with a vernier caliper. The measured area is considerably less than that estimated assuming rectangular cross-section and slightly less than that estimated on the assumption of elliptical cross-section.

Healing ligament mechanical properties are improved by repair with interpositional allografts but not by concomitant treatment with hyaluronic acid

“…Next, after removing a small portion of the medial femoral condyle, the cross-sectional area of the MCL was measured using a custom designed crosssectional area caliper. 46 A hydration bath was then set up around the joint with 0.9% phosphate-buffered saline (PBS) at 378C. For cyclic force relaxation, the ligament was cycled 30 times at 10 mm/min from the zero position to 0.68 mm displacement at which an average strain of about 3% was produced in the femur-MCL-tibia complex.…”

Ligament creep recruits fibres at low stresses and can lead to modulus‐reducing fibre damage at higher creep stresses: a study in rabbit medial collateral ligament model

“…The MCL length was measured at the transition between periosteal and ligamentous tissue at both femoral and tibia1 insertions using Vernier calipers (accurate to 0.01 mm). For clearance of our area caliper [13], a small portion of the medial femoral condyle lateral to the MCL and distal to the femoral MCL insertion was removed. Then, 5 N of tension was maintained, and the caliper traversed the midsubstance of the ligament.…”

No effect of mop-ending on ligament healing: Rabbit studies of severed collateral knee ligaments

“…Ligament laxity was determined in a manner similar to that of Chimich et al (1991) and the cross-sectional area of the mid-substance of the MCL measured with a specially designed instrument (Shrive et al 1988). Laxity is a low-load measure which can be defined as the distance which the cross-head of the test machine travels, going from joint compression to the point where the MCL first experiences tension (Chimich et al 1990).…”