Vertebral balloon kyphoplasty versus vertebral body stenting in non-osteoporotic vertebral compression fractures at the thoracolumbar junction: a comparative radiological study and finite element analysis (BONEXP study).

OBJECTIVE: To compare radiologically balloon kyphoplasty (BKP) and vertebral compression fracture (VCF) expansion and corroborate with a finite element (FE) analysis. The principle of BKP is to stabilize VCF by restoring vertebral body anatomy using bone expansion and cement filling. More recently, vertebral body stenting (VBS) has been developed to reduce the loss of vertebral height observed after balloon deflation. METHODS: A retrospective, monocentric and continuous study of 60 non-osteoporotic fractures of the thoracolumbar junction treated by vertebral bone expansion was carried out over three years. The main endpoint was radiological correction of vertebral kyphosis (VK) at 3 months. The other studied parameters were vertebral height, index of Farcy, index of Beck, cement leakages and their location. A FE model was developed to analyze effects linked to the stent during cement injection, specifically throughout the risk of cement leakage evaluation. RESULTS: After three months, average reduction of VK was 4.73° ± 4.8° after BKP, and 4.63° ± 2.7° after VBS. There was no difference between the two techniques, but cement leakage was significantly greater with BKP (41.7%) than with VBS (4.2%). FE analysis showed substantial changes of the cement flow orientation in the presence of a stent. CONCLUSION: BKP and VBS offer comparable expansion with no added value of VBS in non-osteoporotic VCF reduction. VBS technique appears to prevent cement leakage due to its mesh architecture hindering the leaking process. In counterpart, such balloon expansion is likely to require higher pressure to deploy the stent. This could be an important parameter to take into account in young patients with high bone density.

Stabilization of the distal radioulnar joint by reconstructing the interosseous membrane's distal oblique bundle: Cadaver study.

INTRODUCTION: The distal radioulnar (DRU) ligaments play a key role in stabilizing the DRU joint. Ligament reconstruction in this area is an accepted treatment. However, another structure may also be a significant DRUJ stabilizer-the distal oblique bundle (DOB) of the interosseous membrane (IOM). Recent studies have described DOB reconstruction methods, which should be compared to DRU ligament reconstruction. METHODS: Twelve upper limbs were used. First, a descriptive anatomy study was done to determine the prevalence and features of the DOB (insertions, thickness, and relationship with DRU ligaments). Second, biomechanical testing was done with the wrist in neutral position, supination, and pronation. Distal radius translation was evaluated first on an intact wrist then evaluated again after creating bidirectional instability. Lastly, the same tests were repeated after DRU reconstruction using the Adams-Berger technique and DOB reconstruction using the Riggenbach technique. RESULTS: The DOB was present in 50% of specimens and was bilateral. Reconstructing the DOB stabilized the wrist to the same degree as the Adams-Berger technique in neutral and pronation (8% residual major instability). Stability was harder to achieve in supination (25% major instability). It was better at controlling posterior radial translation than anterior translation (3% versus 14% major instability). CONCLUSION: DOB reconstruction appears to be a reliable and less invasive treatment option for DRUJ instability since it is extra-articular. However, the wrist's position and the direction of radial translation seem to alter the stabilization's effectiveness. LEVEL OF EVIDENCE: IV; Cadaver study.