Prognostic factors for surgical outcomes including preoperative total knee replacement and knee osteoarthritis status in female patients with lumbar spinal stenosis.

ABSTRACT

STUDY DESIGN: A retrospective clinical case series. OBJECTIVE: To investigate knee osteoarthritis (KOA) and total knee replacement (TKR) status as prognostic factors for surgical outcomes in female patients with lumbar spinal stenosis (LSS). SUMMARY OF BACKGROUND DATA There have been many reports on numerous prognostic factors for surgical outcomes in patients with degenerative lumbar conditions; however, there has been no report on the surgical outcome in patients who underwent spinal surgery with coexisting KOA and TKR. METHODS: This study included 141 female patients (mean age, 67.6 y) who underwent spinal surgery for LSS between January 2006 and December 2010. At 1 year postoperatively, surgical outcomes were measured using the Oswestry disability index (ODI). Various clinical factors including KOA and TKR were analyzed as prognostic factors for surgical outcomes. RESULTS: Mean average scores at preoperative evaluation were 26.1±6.6 in the no KOA group, 23.6±7.9 in the KOA group, and 30.4±6.7 in the TKR group (P<0.05). Mean average scores at postoperative 1 year were 13.8±8.5 in the no KOA group, 16.8±9.5 in the KOA group, and 21.4±5.7 in the TKR group (P<0.05, Mann-Whitney U test). Preoperative ODI scores were shown to be significantly affected by the TKR status only (P<0.05), and were significantly higher in the TKR patient group. ODI scores at postoperative 3 months were significantly correlated with the preoperative ODI and the operational level (P<0.05). At postoperative 1 year, ODI scores were shown to be affected by the operational level, the preoperative ODI, and the presence of advanced radiographic KOA (Kellgren/Lawrence grades III and IV) (P<0.05). CONCLUSIONS: A poor preoperative functional score, the presence of preoperative KOA, and longer operational levels were shown to be poor prognostic factors for the 1-year surgical outcome of LSS. Also, patients in the TKR group showed the worst ODI scores at preoperative and postoperative 1-year evaluations. Consideration of these factors when planning for spine surgery could be helpful in predicting the surgical outcomes of lumbar spinal surgery.