Developing a grading scale for the evaluation of degenerative changes in uncovertebral (Luschka) joints

The study aimed to develop a grading scale for evaluating degenerative changes in uncovertebral joints (UVJs) found on computed tomography (CT) scans, and assess the intra- and inter-rater reliability of this scale. The study included 50 subjects (average age 55.12 ± 13.76 years) referred for CT examinations due to cervical complaints. Three researchers developed a reading protocol using a semiquantitative grading scale of UVJ degenerative changes. CTs were read and reread several times to refine the protocol. Subsequently, the reader read and reread 20 CTs (C3-C7 bilateral, altogether 200 UVJs) 2 weeks apart in order to assess the intra-rater reliability. The second reader, after the training, read the same 20 CTs (yet, C4-C6 bilateral, altogether 120 UVJs) in order to assess the inter-rater reliability. The additional 30 CTs were evaluated to analyze the prevalence and associations between the studied parameters. The final grading scale included joint space narrowing, osteophyte, subchondral sclerosis, subchondral cyst, hypertrophy, cortical erosion, and vacuum phenomenon. The intra-rater agreement ranged from very good in joint space narrowing (k = 0.757), osteophyte grade (k = 0.748), subchondral cyst (k = 0.716), hypertrophy (k = 0.728), vacuum phenomenon (k = 0.712) to good (k = 0.544) in subchondral sclerosis, and fair in cortical erosion (k = 0.36). For the overall UVJ degeneration grade, the intra-rater agreement was very good (k = 0.616) and the inter-rater reliability was good (k = 0.468). 77.6% of the evaluated UVJs exhibited some degenerative changes. Our grading scale is the first to evaluate UVJs presenting good-very good intra-rater and inter-rater reliability which can be utilized in further clinical studies and assess degenerative changes in UVJs.