Rodeo Scott A, Potter Hollis G, Kawamura Sumito, Turner A Simon, Kim Hyon Jeong, Atkinson Brent L
The Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
J Bone Joint Surg Am. 2007 Nov;89(11):2485-97. doi: 10.2106/JBJS.C.01627.
Clinical studies have demonstrated a high rate of incomplete healing of rotator cuff tendon repair. Since healing of such a repair is dependent on bone ingrowth into the repaired tendon, we hypothesized that osteoinductive growth factors would improve rotator cuff tendon-healing.
Seventy-two skeletally mature sheep underwent detachment of the infraspinatus tendon followed by immediate repair. The animals received one of three treatments at the tendon-bone interface: (1) an osteoinductive bone protein extract on a Type-I collagen sponge carrier, (2) the collagen sponge carrier alone, and (3) no implant. The animals were killed at six and twelve weeks, and the repaired rotator cuff was evaluated with use of magnetic resonance imaging, plain radiographs, histologic analysis, and biomechanical testing.
A gap consistently formed between the end of the repaired tendon and bone in this model, with reparative scar tissue and new bone spanning the gap. Magnetic resonance imaging showed that the volume of newly formed bone (p < 0.05) and soft tissue (p < 0.05) in the tendon-bone gap were greater in the growth factor-treated animals compared with the collagen sponge control group at both time-points. Histologic analysis showed a fibrovascular tissue in the interface between tendon and bone, with a more robust fibrocartilage zone between the bone and the tendon in the growth factor-treated animals. The repairs that were treated with the osteoinductive growth factors had significantly greater failure loads at six weeks and twelve weeks (p < 0.05); however, when the data were normalized by tissue volume, there were no differences between the groups, suggesting that the treatment with growth factor results in the formation of poor-quality scar tissue rather than true tissue regeneration. The repairs that were treated with the collagen sponge carrier alone had significantly greater stiffness than the growth factor-treated group at twelve weeks (p = 0.005).
This model tests the effects of growth factors on scar tissue formation in a gap between tendon and bone. The administration of osteoinductive growth factors resulted in greater formation of new bone, fibrocartilage, and soft tissue, with a concomitant increase in tendon attachment strength but less stiffness than repairs treated with the collagen sponge carrier alone.
临床研究表明，肩袖肌腱修复的愈合不完全率很高。由于这种修复的愈合依赖于骨长入修复的肌腱，我们推测骨诱导生长因子会改善肩袖肌腱的愈合。
72只骨骼成熟的绵羊接受冈下肌腱离断，然后立即进行修复。动物在肌腱 - 骨界面接受三种治疗之一：（1）I型胶原海绵载体上的骨诱导骨蛋白提取物，（2）单独的胶原海绵载体，（3）不植入。在6周和12周时处死动物，使用磁共振成像、X线平片、组织学分析和生物力学测试对修复的肩袖进行评估。
在该模型中，修复的肌腱末端与骨之间始终形成间隙，有修复性瘢痕组织和新骨跨越该间隙。磁共振成像显示，与胶原海绵对照组相比，在两个时间点，生长因子治疗组的肌腱 - 骨间隙中新形成的骨体积（p < 0.05）和软组织体积（p < 0.05）更大。组织学分析显示肌腱与骨界面有纤维血管组织，生长因子治疗组的骨与肌腱之间有更厚的纤维软骨区。用骨诱导生长因子治疗的修复在6周和12周时的破坏载荷明显更大（p < 0.05）；然而，当数据按组织体积归一化时，各组之间没有差异，这表明生长因子治疗导致形成质量较差的瘢痕组织而非真正的组织再生。单独用胶原海绵载体治疗的修复在12周时的刚度明显高于生长因子治疗组（p = 0.005）。
该模型测试了生长因子对肌腱与骨之间间隙中瘢痕组织形成的影响。给予骨诱导生长因子导致新骨、纤维软骨和软组织形成增加，同时肌腱附着强度增加，但刚度低于单独用胶原海绵载体治疗的修复。
