Introduction: Currently, percutaneous vertebroplasty and kyphoplasty are commonly used for the treatment of vertebral osteoporotic compression fractures (Phillips et al., 2003). Even without fractures, an osteoporotic vertebral body may develop some structural modifications with dystrophic features, defined as “intravertebral clefts” and “intravertebral vacuum” (Missori et al, 2005). These conditions may be painful and the MRI is the imaging technique of choice for their evaluation.

Materials and methods: A prospective consecutive series of 21 elderly patients with pain in the thoracolumbar or lumbar spine were evaluated. MRI findings showed modifications of the vertebral body consistent with algodystrophy. Lesions were treated by means of percutaneous augmentation with PMAA, using a single pedicle approach. The outcomes of such procedure were evaluated with a visual analogue scale for pain (Chen et al, 2005).

Results and conclusions: Percutaneous augmentation has not determined any complications neither early nor late. Outcomes have showed to be good or excellent, except for a patient with insufficient amount of injected PMMA. Augmentation of the vertebral body showed to be effective in reducing or solving pain, in spite of the biomechanical alterations due to algodystrophic phenomena. During kyphoplasty, particularly when performed for painful Schmorl nodes, balloon inflation creates a positive pressure room inside the vertebral body opposed to the negative pressure caused by abnormality of the discovertebral junction. This phenomenon makes it possible to fill the vacuum with PMMA without the risk of cement leakage.

Unlike tri-compartmental arthroplasty, unicompartmental knee arthroplasties (UKAs) correct only osteochondral condylar defects and do not include any ligament balancing. Pre-operative deformities of more than 20° strongly suggest that UKA is not indicated. Best results are generally obtained by avoiding hypercorrection and not exceeding 5° of residual deformity post-operatively. Since 1997, 112 UKAs have been implanted. We performed tibial osteotomies with respect to tibial plateau inclination in the frontal plane (metaphyseal axis). Our patients were pre-operatively studied and then re-evaluated after a mean follow-up of 4 years. We used the GIUM (Gruppo Italiano Utilizzatori Monocompartimentali) scoring system. Pre-operative and post-operative radiograms from all patients were collected, and then we correlated the amount of correction of lower limb mechanical axis with GIUM score for each patient. Mean pre-operative mechanical axis of the lower limb showed a varus deformity of 7.43°, whereas post-operative values averaged 5.56° of varus deformity, with a minimal valgus correction of the deformity. Thus, correction of angular deformity was statistically negligible (p> 0.5). Mean pre-operative GIUM score was 20.3, whereas mean post-operative score was 71.6 (p< 0.001). Correlation between entity of correction and GIUM score was significant (r=0.76). The amount of angular correction of the mechanical axis of the lower limb was statistically significant in influencing functional outcomes (p< 0.05). The best results are obtained by correcting excessively valgus knees to a physiologic range, while varus knees have to be minimally corrected. The worst results are obtained with greatest modifications of the mechanical axis of the lower limb.