Markolf Keith, Davies Mark, Zoric Bojan, McAllister David
Biomechanics Research Section, David Geffen School of Medicine at UCLA, University of California, Los Angeles, Los Angeles, California 90095-6902, USA.
Am J Sports Med. 2003 Sep-Oct;31(5):673-9. doi: 10.1177/03635465030310050701.
Posterior laxity occurring after posterior cruciate ligament reconstruction with a tibial tunnel could be related to thinning and permanent elongation of the graft as it is cyclically loaded in vivo.
The orientation and position of the bone block within the tibial tunnel will have a significant effect on thinning and elongation of the graft after cyclic loading.
Controlled laboratory study.
In test series 1 (27 fresh-frozen graft pairs), all bone blocks were positioned flush with the posterior opening of the tibial tunnel; 1 graft was oriented with the bone block facing posteriorly, whereas its pair was tested with the bone block facing anteriorly. In test series 2 (20 graft pairs), all grafts were oriented with the bone block facing posteriorly; 1 graft had the bone block positioned flush with the posterior tunnel opening, whereas its pair was tested with the bone block recessed 1 cm from the posterior opening.
In series 1, 3 of 27 grafts with posterior bone block orientations failed at the tunnel edge before 2000 cycles of testing could be completed; all specimens with anterior bone block placements survived the testing intact. In series 2, 3 of 20 grafts with recessed bone blocks failed at the tunnel edge, whereas all those with flush bone blocks survived.
The best position for the bone block of a bone-patellar tendon-bone graft was flush with the posterior tunnel opening with the bone block facing anteriorly in the tibial tunnel.
采用胫骨隧道进行后交叉韧带重建术后出现的后方松弛可能与移植物在体内反复加载时发生变薄和永久性延长有关。
胫骨隧道内骨块的方向和位置对反复加载后移植物的变薄和延长有显著影响。
对照实验室研究。
在试验系列1（27对新鲜冷冻移植物）中，所有骨块均与胫骨隧道后开口齐平定位；1个移植物的骨块朝后，而其配对移植物测试时骨块朝前。在试验系列2（20对移植物）中，所有移植物的骨块均朝后；1个移植物的骨块与隧道后开口齐平定位，而其配对移植物测试时骨块从后开口向后缩进1厘米。
在系列1中，27个骨块朝后的移植物中有3个在完成2000次测试循环前于隧道边缘处失效；所有骨块朝前放置的标本在测试中均完整存活。在系列2中，20个骨块缩进的移植物中有3个在隧道边缘处失效，而所有骨块齐平的移植物均存活。
髌腱-骨移植物骨块的最佳位置是与胫骨隧道后开口齐平，且骨块在隧道内朝前。
