Barber F Alan, Dockery W Dee
Plano Orthopedic and Sports Medicine Center, Plano, Texas 75093, USA.
Arthroscopy. 2006 Aug;22(8):820-6. doi: 10.1016/j.arthro.2006.04.096.
To evaluate the long term in vivo degradation of poly-L-lactic acid (PLLA) interference screws with computed tomography (CT) and radiography as used in patellar tendon autograft anterior cruciate ligament (ACL) reconstruction.
A total of 20 patients who had undergone patellar tendon autograft ACL reconstruction fixed with PLLA screws at least 7 years earlier were evaluated by physical examination, radiography, and CT to determine whether PLLA screw reabsorption and bone ingrowth had occurred. This study was granted Institutional Review Board approval. Lysholm, Tegner, Cincinnati, and International Knee Documentation Committee (IKDC) scores were obtained. CT data were measured in Hounsfield units.
In all, 15 men and 5 women were evaluated 104 months after surgery (range, 89 to 124 months). CT and radiography demonstrated that the bone plug had fused to the tunnel wall, and that no intact interference screw was left. A parallel, threaded, and corticated screw tract was visible adjacent to the bone plug. No bone ingrowth had occurred at the screw site, although, occasionally, minimal calcification was seen. This was never as dense as cancellous bone, and no trabeculae were ever present. No positive pivot-shift test results were obtained. Lysholm, Tegner, and Cincinnati scores were 83, 5.6, and 75, respectively, at follow-up. Average KT difference was 0.7 mm.
PLLA interference screws completely degraded, and the resulting area demonstrated a low Hounsfield count, consistent with soft tissue 7 years after insertion. No significant bone ingrowth occurred at the screw site. Femoral and tibial ACL tunnels were absent of anything but fibrous tissue and usually had a sclerotic cortical lining.
PLLA biodegradable ACL screws eventually disappear completely. PLLA material is not replaced by bone. ACL graft tunnels are filled with nonossified material. This study provides a baseline for comparison with other biodegradable interference screws that may encourage bone ingrowth as they degrade.
Level IV (no or historical control).
采用计算机断层扫描（CT）和X线摄影评估聚左旋乳酸（PLLA）干涉螺钉在自体髌腱前交叉韧带（ACL）重建中体内的长期降解情况。
对至少7年前接受自体髌腱ACL重建并用PLLA螺钉固定的20例患者进行体格检查、X线摄影和CT检查，以确定是否发生了PLLA螺钉吸收和骨长入。本研究获得了机构审查委员会的批准。获取了Lysholm、Tegner、辛辛那提和国际膝关节文献委员会（IKDC）评分。CT数据以亨氏单位测量。
总共对15名男性和5名女性在术后104个月（范围89至124个月）进行了评估。CT和X线摄影显示骨栓已与隧道壁融合，且未留下完整的干涉螺钉。在骨栓旁可见一条平行、有螺纹且有皮质的螺钉通道。在螺钉部位未发生骨长入，不过偶尔可见少量钙化。其密度从未达到松质骨的密度，也从未出现小梁结构。未获得阳性轴移试验结果。随访时Lysholm、Tegner和辛辛那提评分分别为83、5.6和75。平均KT差值为0.7 mm。
PLLA干涉螺钉完全降解，降解后的区域亨氏计数较低，与植入7年后的软组织情况一致。在螺钉部位未发生明显的骨长入。股骨和胫骨ACL隧道除纤维组织外无其他物质，通常有一层硬化的皮质内衬。
PLLA可生物降解的ACL螺钉最终会完全消失。PLLA材料不会被骨替代。ACL移植物隧道充满未骨化的物质。本研究为与其他可能在降解时促进骨长入的可生物降解干涉螺钉进行比较提供了基线。
IV级（无对照或历史对照）。
