Disk degeneration in lumbar spine precedes osteoarthritic changes in hip

It is not clear whether spinal degeneration leads to hip arthritis, or hip arthritis leads to spinal degeneration. We conducted a study to determine which degenerative process precedes the other. We examined 340 cadaveric human specimens from the Hamann-Todd Osteological Collection (Cleveland, Ohio). Lumbar endplate degeneration was graded on a scale of 0 to 4, and hip degeneration on a scale of 0 to 3. Linear regression was used to analyze the relationship between hip osteoarthritis (OA) and lumbar degenerative disk disease (DDD). Exact tests were used to identify differences in each age group. Hip OA was significantly associated with endplate degeneration at the L1, L3, and L5 levels (P<.02). Of the specimens younger than 29 years, 35% had evidence of DDD in at least 1 lumbar level, and 17% of hip OA changes. At 70 years, 100% of the specimens had evidence of DDD and 50% of hip OA changes. There was a significant association between lumbar DDD and hip OA changes (P<.05). Early lumbar DDD was twice as common as hip OA changes in the early 20s age range. These findings suggest that lumbar degeneration precedes hip degeneration and may be a causative factor for hip OA.