Spontaneous Reduction Finding: Magnetic Resonance Imaging Evaluation of Segmental Instability in Spondylolisthesis

STUDY DESIGN: Retrospective chart review. PURPOSE: To assess whether spontaneous reduction of spondylolisthesis, as seen on magnetic resonance imaging (MRI), is related to the degree of segmental instability and low back pain. OVERVIEW OF LITERATURE: The flexion-extension radiographs obtained in the sagittal plane are frequently used when segmental instability of spondylolisthesis is evaluated. METHODS: We retrospectively reviewed 137 patients and measured the differences of the percentage of sagittal translation and sagittal angulation to determine the segmental instability between the flexion and extension radiographs, and the spontaneous reduction on MRI. We then compared the degrees of segmental instability and the degrees of spontaneous reduction. To assess the effect of low back pain on segmental motion in regards to the flexion-extension radiographs, we compared the preoperative visual analogue scales (VAS) score for low back pain between the more and the less spontaneous reduction groups. RESULTS: The mean degree of spontaneous reduction was 5.2%. A statistically significant correlation was found between the sagittal translation on the flexion-extension radiographs and the degree of spontaneous reduction (r = 0.557, p < 0.001) and between the sagittal angulation on the flexion-extension radiographs and the degree of spontaneous reduction (r = 0.215, p = 0.012). The preoperative VAS scores for low back pain of the more spontaneous reduction group and the less spontaneous reduction group were 4.6 and 3.6 points, respectively, and this difference was statistically significant (p = 0.002). CONCLUSIONS: Spontaneous reduction of spondylolisthesis on MRI was found to be closely related to segmental instability, and the degree of spontaneous reduction seen on MRI could be useful for the evaluation of segmental instability in patients with spondylolisthesis, especially with severe low back pain.

Eight to Eighteen Years Follow Up Study of Primary Hybrid Total Hip Arthroplasty Using a Precoat Femoral Stem / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to evaluate the 15.5 year long term survival rate of the Precoat femoral stem. MATERIALS AND METHODS: We reviewed the results of 105 primary hybrid total hip replacements (98 patients) that were performed by one surgeon between October 1990 and August 1995 using a cemented polymethyl-methacrylate coated femoral prosthesis (Precoat) and contemporary cementing techniques. Thirty four patients (34 hips) died and seventeen patients (17 hips) were lost to follow-up. Forty seven patients (54 hips) were available for clinical follow-up, with an average follow-up period of 15.5 years (range: 8.4 to 18.3 years). The average age of the patients at the time of the index operation was 46 years (range: 22 to 67 years). There were 32 male patients (37 hips) and 15 female patients (17 hips). RESULTS: For the acetabular component, 15 hips (27.8%) were revised for cup loosening and isolated liner exchange was performed in 12 hips (22.2%) for liner wear and osteolysis. For the femoral component, 12 hips (22.2%) were revised due to aseptic loosening. Of these twelve hips, 3 hips had Grade B cement mantles and 9 had Grade C cement mantles. The clinical results of the 54 retained hips were good or excellent in 52 hips (96.3%) with the average Harris hip score being 88 points (range: 72 to 96 points). CONCLUSION: The mean 15.5 years' survival rate of the Precoat cemented femoral stem was 78%. We think that there were several factors for the failure of femoral stem fixation, including age, physical activity and the body weight, as well as the stem design and the surgical technique had an influence on the stem's survival.