Department of Orthopedics, Kaiser Permanente Los Angeles Medical Center, Los Angeles, California, U.S.A.
Orthopedic Associates of Hartford, Hartford, Connecticut, U.S.A.
Arthroscopy. 2017 Nov;33(11):2038-2044. doi: 10.1016/j.arthro.2017.06.043. Epub 2017 Aug 24.
To measure the patellofemoral contact pressure in early flexion after a tibial tubercle distalization osteotomy.
Ten matched-pair fresh-frozen cadaveric knees were studied. The average Blackburne-Peel ratio of the native knees was 0.91. The knees were placed on a testing rig, with a fixed femur and tibia mobile through 90° of flexion. Individual quadriceps heads and the iliotibial band were separated and loaded with 205 N in anatomic directions using a weighted pulley system. A straight tubercle distalization osteotomy of 1 cm was performed and fixed with screws, with and without a lateral release. Patellofemoral contact pressures were measured at 0°, 10°, 20°, 30°, 45°, 60°, and 90° of flexion using pressure-sensitive films on the medial trochlea and lateral trochlea. Contact force, area, and pressure were measured in the following states: (1) in the native knee, (2) after distalization, and (3) after distalization with lateral release.
The average Blackburne-Peel ratio after distalization was 0.64. Tibial tubercle distalization resulted in a 6-fold increase in mean contact pressure at 0° (0.15 MPa vs 0.90 MPa, P < .001) and a 55% increase at 10° of flexion (0.70 MPa vs 1.09 MPa, P = .02). Mean contact pressure was similar from 20° to 90° of flexion (P > .1). After distalization, the total contact area was significantly higher at 0° of flexion (17.7 mm vs 58.4 mm, P = .02). Lateral release after distalization did not significantly change contact pressure (P > .21).
Our results suggest that patella baja, as a result of excessive patellar distalization, can cause increased patellofemoral contact pressures during early flexion at 0° and 10°. No changes were seen in contact pressure from 20° to 90°.
Care should be taken to prevent excessive distalization of the patella to avoid patella baja and increased patellofemoral contact pressures during early flexion.
测量胫骨结节下极移截骨术后早期屈膝时髌股关节接触压力。
研究了 10 对匹配的新鲜冷冻尸体膝关节。正常膝关节的平均 Blackburne-Peel 比值为 0.91。膝关节置于测试架上，股骨固定，胫骨通过 90°的屈曲活动。使用加权滑轮系统，以解剖方向向各个股四头肌头和髂胫束施加 205 N 的力。进行 1 cm 的直胫骨结节下极移截骨术，并通过螺钉固定，同时进行或不进行外侧松解。在 0°、10°、20°、30°、45°、60°和 90°的屈曲位，使用内侧滑车和外侧滑车的压力敏感胶片测量髌股关节接触压力。在以下状态下测量接触力、面积和压力：（1）在正常膝关节中，（2）在移截骨术后，（3）在移截骨术后外侧松解时。
移截骨术后的平均 Blackburne-Peel 比值为 0.64。胫骨结节下极移截骨术后，0°时平均接触压力增加了 6 倍（0.15 MPa 比 0.90 MPa，P <.001），10°时增加了 55%（0.70 MPa 比 1.09 MPa，P <.02）。从 20°到 90°的屈曲位，平均接触压力相似（P >.1）。移截骨术后，0°时的总接触面积显著增大（17.7 mm 比 58.4 mm，P <.02）。外侧松解后，接触压力无明显变化（P >.21）。
我们的研究结果表明，由于髌骨过度下极移截骨，髌骨低位可导致 0°和 10°早期屈曲时髌股关节接触压力增加。从 20°到 90°的屈曲位，接触压力没有变化。
应注意防止髌骨过度下极移截骨，以避免髌骨低位和早期屈曲时髌股关节接触压力增加。
