Quantitative determination of articular pressure in the human shoulder joint

Abstract

The objective of this study was to determine experimentally the effect of individual variations in articular surface geometry on the shoulder joint pressure distribution in functionally important arm positions. The location and size of the load-bearing areas and maximal pressures of 10 cadaver shoulder joints were examined at 30 degrees, 90 degrees, and 150 degrees of abduction (+/-90 degrees external rotation) and 120 degrees flexion with pressure-sensitive film. Only parts of the glenoid cavity were involved in the load transfer, some specimens showing central and other bicentric (superior-inferior) pressure maxima during abduction and flexion. The load-bearing areas were more central at external rotation, suggesting that the humeral head is not a perfect sphere. The maximal pressure was recorded at 90 degrees of abduction with 90 degrees external rotation, with 5.1 MPa for the elevation for single- and >10 MPa for double-arm weight. The study demonstrates that shoulder joint pressure cannot be calculated analytically but depends on subtle variations of joint incongruity.

Anisotropy, inhomogeneity, and tension–compression nonlinearity of human glenohumeral cartilage in finite deformation

“…Focal areas of GHJ cartilage degeneration have been observed to develop at the articular contact region when the arm elevation is between 60° and 100° (Neer, 1974), where maximal joint forces of 44% to 90% of body weight may occur according to theoretical predictions (Van der Helm, 1994), and anatomic measurements during static (Poppen and Walker, 1978) or dynamic (Apreleva et al, 2000) abduction. Conzen and Eckstein (2000) measured GHJ articular contact pressure and found that the maximum pressure of 5.1 MPa was recorded at the 90° of abduction with 90° external rotation. Furthermore, the surface area disparity (1:3 surface area ratio) between the glenoid and humeral head results in substantial differences in the duration of loading (duty cycle), with the glenoid cartilage subjected to a greater duty cycle during daily joint function (Soslowsky et al, 1992a).…”

Effect of lateral meniscus allograft on shoulder articular contact areas and pressures

“…Traditionally, Fuji film (Fuji Photo Film, New York, NY, USA) has been used to determine contact pressures across joints in other research endeavors. 10,30,32,41 We believe, as do other investigators, that the Tekscan technology allows for a more in-depth, accurate, and reproducible data collection. 11,16,42 This study demonstrated the effect of placing a lateral meniscus allograft between the humeral head and glenoid and applying compressive loads of 220 N and 440 N. When compared with the normal glenohumeral articulation, mean force in the lateral meniscus allograft group decreased by 11% during the 220-N testing condition and by 9% during the 440-N testing condition.…”

“…2,3,18,27,38 Other authors have critically evaluated the contact areas and pressures of an intact and pathologic glenohumeral joint. 10,16,34,35,41 Some of these studies have reported an increase in contact area and pressure as arm abduction approaches 120°, which begins to decrease beyond this elevation. 10,35,41 Under abnormal conditions, these contact areas are increased as a result of contractures, biconcentric loading conditions, and loss of soft-tissue restraints.…”

“…10,16,34,35,41 Some of these studies have reported an increase in contact area and pressure as arm abduction approaches 120°, which begins to decrease beyond this elevation. 10,35,41 Under abnormal conditions, these contact areas are increased as a result of contractures, biconcentric loading conditions, and loss of soft-tissue restraints. 10,13 In the glenohumeral joint, in situ compressive properties of the glenoid labrum are similar to those of knee menisci and may have some similar functions.…”

“…10,35,41 Under abnormal conditions, these contact areas are increased as a result of contractures, biconcentric loading conditions, and loss of soft-tissue restraints. 10,13 In the glenohumeral joint, in situ compressive properties of the glenoid labrum are similar to those of knee menisci and may have some similar functions. 8 An allograft may be considered in a primary setting when the age, occupation, and activity level of the patient create concern regarding glenoid component longevity.…”