Clinical and radiological outcomes following microscopic decompression utilizing tubular retractor or conventional microscopic decompression in lumbar spinal stenosis with a minimum of 10-year follow-up.

Satisfactory short- and mid-term results have been observed following microscopic decompression with tubular retractor (MDT) and conventional microscopic decompression (CMD) in lumbar spinal stenosis (LSS). It is not yet clear which surgical procedure is the optimal treatment for LSS, especially in long-term follow-up period. To the best of our knowledge, there is no comparative study analyzing the clinical-radiological outcomes of MDT and CMD over a 10-year follow-up periods. The purpose of this study was to evaluate and compare clinical and radiological outcomes of MDT and CMD over a 10-year follow-up period in patients with LSS. Of total 121 patients, 102 patients (53 MDT and 49 CMD) were followed for at least 10 years following MDT and CMD for LSS. We retrospectively reviewed surgical results and clinical outcomes based on the visual analogue scale, McNab's criteria, and the Oswestry Disability Index, and radiological analysis results with the parameters, including the change of disk height and intervertebral distance, obtained preoperatively and 3- and 6-month, and 1-, 6-, and 10-year postoperatively. There was no significant difference in patient demographics between the two groups. Five patients (two in MDT, three in CMD) required re-operation for re-stenotic change of the affected segment. The number of patients requiring re-operation was not significantly different between the two groups (p > 0.05). No statistically significant differences were observed between the groups in a long-term follow-up period after a 3-month follow-up (p > 0.05). However, in the acute postoperative phase of <3-month postoperatively, MDT appears to result in less postoperative pain and better clinical outcomes compared with the CMD. In conclusion, despite relatively small sample size with retrospective design, our study suggested that MDT appears to result in less postoperative pain and better clinical outcomes in the acute postoperative period of <3 months, but both MDT and CMD were no significant differences in clinical and radiological outcomes after that time.

The position of the tibial component affecting the postoperative mechanical axis in total knee arthroplasty.

The purpose is to identify whether the position of the tibial component in relation to the anatomical axis affects the postoperative mechanical axis in total knee arthroplasty for Korean patients. Preoperatively, 30 patients with varus deformity lesser than 10° were classified as group A, and 30 patients greater than 10° were classified as group B. Postoperatively, the distance between the midline of the tibial stem and anatomical axis (medial offset) was measured. The medial offsets were 2.5±1.9 mm in group A and 3.9±2.7 mm in group B (P=.021). The postoperative mechanical axes were varus 1.3±1.2° in group A and varus 2.5±2.0° in group B (P=.004). We think that the medial position of tibial component in relation to the anatomical axis affects the measurement of postoperative mechanical axis in total knee arthroplasty.