Accuracy and reliability testing of two methods to measure internal rotation of the glenohumeral joint.

BACKGROUND: We compared accuracy and reliability of a traditional method of measurement (most cephalad vertebral spinous process that can be reached by a patient with the extended thumb) to estimates made with the shoulder in abduction to determine if there were differences between the two methods. METHODS: Six physicians with fellowship training in sports medicine or shoulder surgery estimated measurements in 48 healthy volunteers. Three were randomly chosen to make estimates of both internal rotation measurements for each volunteer. An independent observer made objective measurements on lateral scoliosis films (spinous process method) or with a goniometer (abduction method). Examiners were blinded to objective measurements as well as to previous estimates. RESULTS: Intraclass coefficients for interobserver reliability for the traditional method averaged 0.75, indicating good agreement among observers. The difference in vertebral level estimated by the examiner and the actual radiographic level averaged 1.8 levels. The intraclass coefficient for interobserver reliability for the abduction method averaged 0.81 for all examiners, indicating near-perfect agreement. Confidence intervals indicated that estimates were an average of 8° different from the objective goniometer measurements. Pearson correlation coefficients of intraobserver reliability for the abduction method averaged 0.94, indicating near-perfect agreement within observers. Confidence intervals demonstrated repeated estimates between 5° and 10° of the original. CONCLUSIONS: Internal rotation estimates made with the shoulder abducted demonstrated interobserver reliability superior to that of spinous process estimates, and reproducibility was high. On the basis of this finding, we now take glenohumeral internal rotation measurements with the shoulder in abduction and use a goniometer to maximize accuracy and objectivity.

Identification of a molecular recognition role for the activation loop phosphotyrosine of the SRC tyrosine kinase.

A human cDNA phage display library screen, using a phosphopeptide designed to mimic the activation loop phosphotyrosine of the Src tyrosine kinase, has identified the N-terminal SH2 domain of the p85 regulatory subunit of phosphatidyl inositol-3 kinase (PI3K) as an interacting recognition domain. Activation loop phosphorylation is known to play a conformational role in kinase activation, but is largely not thought to play a role in protein/protein recognition. Affinity chromatography and biochemical evaluation in mouse fibroblast cells has confirmed the dependence of this interaction on both the Src activation loop phosphotyrosine and the N-terminal SH2 domain of PI3K.