Belkin Nicole S, Meyers Kathleen N, Redler Lauren H, Maher Suzanne, Nguyen Joseph T, Shubin Stein Beth E
Sports Medicine and Shoulder Service, Columbia University Orthopedics, New York, New York, U.S.A..
Department of Biomechanics, New York, New York, U.S.A.; Hospital for Special Surgery, New York, New York, U.S.A.
Arthroscopy. 2020 Dec;36(12):3031-3036. doi: 10.1016/j.arthro.2020.01.035. Epub 2020 Feb 5.
To investigate alterations in technique for medial patellofemoral ligament (MPFL) reconstruction in the setting of patella alta and describe the effect of these alterations on MPFL anatomometry.
Ten cadaveric knees were used. Four candidate femoral attachment sites of MPFL were tested. The attachment sites were Schottle's point (SP), 5 mm distal to SP, 5 mm proximal to SP, and 10 mm proximal to SP. A suture anchor was placed at the upper 40% of the medial border of the patella with the emanating suture used to simulate the reconstructed ligament. MPFL maximum length change was calculated through a range of motion between 0° and 110°. Recordings at all 4 candidate femoral attachments sites were repeated after a flat tibial tubercle osteotomy and transfer to achieve alta as measured by the Caton-Deschamps Index (CDI) of 1.3, 1.4, and 1.5.
The 10 specimens had an average CDI of 0.99, range 0.87 to 1.16. In the native tibial tubercle condition, SP was more isometric through 20° to 70° range of motion, or anatomometric, than any other candidate femoral attachment location. With patella alta with a CDI of 1.3 and 1.4, attachment site 5 mm proximal to SP exhibited more anatomometry than SP. With patella alta with a CDI of 1.5, attachment site 10 mm proximal to SP exhibited more anatomometry than SP.
Increased patella alta significantly alters MPFL anatomometry. With increasing degrees of patella alta, more proximal candidate femoral attachment sites demonstrate decreased change in length compared with SP. None of the varied femoral attachments produced anatomometry over the entirety of the flexion range from 20° to 70°, suggesting that in cases of significant patella alta, proximalization the femoral attachment site of MPFL reconstruction may be necessary to achieve an anatomometric MPFL reconstruction.
A standardized, isolated MPFL reconstruction may be prone to failure in the setting of patella alta, given the anisometry demonstrated. Alternative femoral attachment sites for MPFL reconstruction should be considered in these patients.
研究在高位髌骨情况下内侧髌股韧带（MPFL）重建技术的改变，并描述这些改变对MPFL解剖测量学的影响。
使用10具尸体膝关节。测试了MPFL的四个候选股骨附着点。附着点分别为朔特尔点（SP）、SP远端5mm处、SP近端5mm处以及SP近端10mm处。在髌骨内侧缘上40%处放置一枚缝线锚钉，用引出的缝线模拟重建韧带。通过0°至110°的活动范围计算MPFL的最大长度变化。在进行胫骨结节截骨并移位以达到高位髌骨（通过Caton-Deschamps指数（CDI）测量，分别为1.3、1.4和1.5）后，重复对所有4个候选股骨附着点的记录。
10个标本的平均CDI为0.99，范围为0.87至1.16。在胫骨结节正常状态下，在20°至70°的活动范围内，SP比其他任何候选股骨附着位置更具等长性，即解剖测量学特征。当CDI为1.3和1.4的高位髌骨时，SP近端5mm处的附着点比SP表现出更多的解剖测量学特征。当CDI为1.5的高位髌骨时，SP近端10mm处的附着点比SP表现出更多的解剖测量学特征。
高位髌骨程度增加会显著改变MPFL的解剖测量学。随着高位髌骨程度的增加，与SP相比，更多近端的候选股骨附着点长度变化减小。在20°至70°的整个屈曲范围内，没有一个不同的股骨附着点能产生解剖测量学上的理想效果，这表明在严重高位髌骨的情况下，将MPFL重建的股骨附着点向近端移位可能是实现解剖学MPFL重建所必需的。
鉴于所显示的不等长性，标准化的、孤立的MPFL重建在高位髌骨情况下可能容易失败。对于这些患者，应考虑MPFL重建的替代股骨附着点。
