Bone & Joint Sports Medicine Institute, Naval Medical Center, Portsmouth, Virginia, USA.
Department of Radiology, Naval Medical Center, Portsmouth, Virginia, USA.
Orthop J Sports Med. 2013 Nov 15;1(6):2325967113512460. doi: 10.1177/2325967113512460. eCollection 2013 Nov.
Acute patellar dislocation (APD) is a common knee injury in children. The pattern and frequency of injury to the medial patellofemoral ligament (MPFL) is different in pediatric compared with adult populations.
To report on injury patterns sustained to the MPFL after APD in children and to determine whether predisposing factors for APD cited in adults hold true in the pediatric population.
Case series; Level of evidence, 4.
Magnetic resonance imaging (MRI) studies were reviewed for 36 children sustaining APD. Evidence of injury to the MPFL was documented, and when the MPFL was torn, the location of tear was determined. Presence of trochlear dysplasia, patella alta, tibial tubercle-trochlear groove (TTTG) distance, and thickness of the lateral patellofemoral retinaculum (LPR) were recorded and correlated with MPFL tear.
Of the 36 patients sustaining APD, only 16 tore the MPFL. The location of MPFL tear was equally divided between the origin, the insertion, or both, with no case of midsubstance tear. There was a significant correlation identified between MPFL rupture and both LPR thickness greater than 3 mm and TTTG distance greater than 19 mm.
The MPFL does not always tear in children who sustain APD, and the tear location is variable. A thickened LPR and increased TTTG distance predispose to MPFL tear.
急性髌骨脱位（APD）是儿童常见的膝关节损伤。与成人相比，儿童的内侧髌股韧带（MPFL）损伤模式和频率有所不同。
报告儿童 APD 后 MPFL 的损伤模式，并确定在成人中导致 APD 的诱发因素是否在儿童人群中成立。
病例系列；证据水平，4 级。
对 36 例发生 APD 的儿童进行磁共振成像（MRI）研究回顾。记录 MPFL 损伤的证据，当 MPFL 撕裂时，确定撕裂的位置。记录滑车发育不良、髌骨高位、胫骨结节-滑车沟（TTTG）距离和外侧髌股支持带（LPR）的厚度，并与 MPFL 撕裂相关联。
在 36 例发生 APD 的患者中，只有 16 例撕裂了 MPFL。MPFL 撕裂的位置在起点、止点或两者之间平均分布，没有中间撕裂的病例。MPFL 断裂与 LPR 厚度大于 3mm 和 TTTG 距离大于 19mm 之间存在显著相关性。
在发生 APD 的儿童中，MPFL 并非总是撕裂，且撕裂位置是可变的。增厚的 LPR 和增加的 TTTG 距离易导致 MPFL 撕裂。
