Effect of Spinal Deformity on Pelvic Orientation from Standing to Sitting Position

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• 作者：Chitranjan S. Ranawat ; MD^a ; Amar S. Ranawat ; MD^a ; Joseph D. Lipman ; MS^b ; Peter B. White ; BA^a ; Morteza Meftah ; MD^c ;
• 关键词：fixed spinal deformity ; functional pelvis ; sagittal pelvic tilt angle ; functional cup anteversion ; standing to sitting
• 刊名：The Journal of Arthroplasty
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：31
• 期：6
• 页码：1222-1227
• 全文大小：1344 K

文摘

The effect of fixed spinal deformities on a functional pelvis from standing to sitting is not fully understood. We aimed to assess the change in preoperative sagittal pelvic tilt angle (SPTA) from standing to sitting in patients undergoing total hip arthroplasty, comparing flexible and fixed spinal deformities.

Methods

Between July 2011 and October 2011, 68 consecutive unilateral total hip arthroplasties were implanted in 68 patients with a mean age of 71 ± 6 years. Fixed spinal deformity was defined as <10° of the change in SPTA from standing to sitting. Preoperative radiographic evaluation included standing (weight-bearing) anteroposterior and lateral pelvic and lumbosacral radiographs and a sitting lateral pelvic radiograph.

Results

The mean standing and sitting SPTA was 3.7° of anterior tilt and 17.7° of posterior tilt, respectively (change of 21.4 ± 12.5°). Seventy-five percent had flexible pelvises, all of which had a posterior tilt from standing to sitting. One patient in the fixed pelvis (1.4%) had a loss of posterior tilt from standing to sitting. The mean change of SPTA from standing to sitting in the fixed and flexible pelvis groups was 5.9 ± 3.5° to 26.7 ± 9.6° of posterior tilt, which was statistically significant (P < .05).

Conclusion

There was a significant change in sagittal pelvic tilt from standing to sitting, especially in patients with a flexible spine, in which the functional anteversion increases with sitting. The patients with a fixed pelvis had significantly less SPTA in standing (less anteversion) with less posterior sagittal tilt in sitting, which should be incorporated in cup positioning.