Background

Aseptic loosening of cemented femoral stems results from migration of wear particles along the bone-cement interface, producing a foreign body reaction. After cement insertion, blood back pressure can disrupt the bone-cement interface, enabling this spread of wear particles. Our study investigates whether altering timing and speed of stem insertion can reduce this risk.

Aims: To study the outcome of lumbar spinal fusions in patients with chronic lower back pain due to degenerative spinal disorders. Methods: 85 patients with DSD’s, a mean age of 46.4 years, back pain for at least 2 years (mean=7.7years) and failed conservative treatment for at least 1 year were admitted to the study. Questionnaires recorded socio-demographic characteristics; changes in pain, clinical findings, disability (Oswestry (ODI)), employment, radiographic fusion, patient satisfaction and complications. All patients had 3, 6, 12 and 24-month follow-ups. Results: There were 37 males (44.9years) and 48 females (47.6 years) with a mean BMI of 24.8; 49% were smokers. Pain improved significantly at 3months (p< 0.001); no deterioration at 2 years with 38.4% having no back pain. Motor (p< 0.01), sensory (p< 0.05) and Oswestry Disability (0.001) improved significantly at 3 months and continued throughout. Unemployment improved significantly 30.4% to 16.5% at 2 years (p< 0.04). Radiographic fusion occurred in 91.8%, instrument failure in 11.8% and 9.4% required re-operation. Patient satisfaction revealed a significant increase in excellent (p< 0.02) and poor (p< 0.03) results. Instrument failure correlated strongly with ODI (r=0.94, p< 0.04). No other significant correlations. Conclusions:With the correct patient selection, lumbar fusions for DSD’s lead to a significantly improved outcome at 2 years, with an acceptable complication rate. There is no correlation between radiographic fusion and outcome, but instrument failure leads to significantly worse outcome