Departments of Radiology, Oslo University Hospital, Oslo, Norway.
Acta Orthop. 2013 Aug;84(4):426-30. doi: 10.3109/17453674.2013.810523. Epub 2013 Jun 25.
Percutaneous physiodesis in the knee region is a well-established method for treating leg-length inequality. Longitudinal growth in the physis is believed to stop almost immediately after the operation. The extent of physis ablation required has never been investigated by any kind of tomography in humans. Using radiostereometric analysis (RSA), we determined when definite growth arrest occurred after surgery. We also studied the correlation between the extent of physis ablation and postoperative growth. Finally, we assessed any bone bridging across the physis.
6, 12, and 30 weeks after surgery, we used RSA to measure longitudinal growth in 27 patients (37 physes) with a mean age of 13 years. CT scanning of the knee region was performed 12 weeks after surgery to measure the percentage of the ablated physis and to determine the distribution of bone bridges across the physis.
RSA showed that growth rate was reduced to less than half of the expected rate after 6 weeks. During the next 6 weeks, the growth ceased completely. CT scans revealed a large variation in the extent of ablated physes (17-69%). In the ablated areas, tissues of various densities were mixed with mature bone. Bridges were found both laterally and medially across the physes in all of the patients. There was a negative correlation between the extent of ablation and total postoperative growth (rho = -0.37, p = 0.03).
Growth across the physis is effectively stopped by percutaneous physiodesis. RSA is well-suited for observation of this phenomenon. Volume CT scanning can be used to detect bone bridges that cross the physis and to calculate the extent of physis ablation.
经皮骺松解术是治疗下肢不等长的一种成熟方法。骺板的纵向生长在手术后几乎立即停止。然而，目前还没有任何一种人体断层扫描技术研究过需要消融骺板的程度。本研究使用放射学体层摄影术（RSA）确定手术后何时发生明确的生长停滞。我们还研究了骺板消融程度与术后生长之间的相关性。最后，我们评估了骺板上任何骨桥形成的情况。
手术后 6、12 和 30 周，我们使用 RSA 测量了 27 例（37 个骺板）年龄平均为 13 岁的患者的纵向生长情况。手术后 12 周对膝关节进行 CT 扫描，以测量消融骺板的百分比，并确定骺板上骨桥的分布。
RSA 显示，6 周后生长速度降低至预期速度的一半以下。在接下来的 6 周内，生长完全停止。CT 扫描显示，消融骺板的程度存在很大差异（17%-69%）。在消融区域，各种密度的组织与成熟骨混合在一起。在所有患者中，骺板的外侧和内侧都发现了桥接。消融程度与总术后生长之间呈负相关（rho = -0.37，p = 0.03）。
经皮骺松解术可有效阻止骺板生长。RSA 非常适合观察这种现象。容积 CT 扫描可用于检测穿过骺板的骨桥，并计算骺板消融的程度。
