Ince Deniz C, Kamenaga Tomoyuki, Kikuchi Kenichi, Clohisy John C, O'Keefe Regis J, Yuh Catherine, Wimmer Markus A, Mell Steven P, Pascual-Garrido Cecilia
Washington University in St Louis School of Medicine, St Louis, Missouri, USA.
Rush University Medical Center, Chicago, Illinois, USA.
Am J Sports Med. 2025 May;53(6):1328-1335. doi: 10.1177/03635465251326888. Epub 2025 Mar 23.
Femoroacetabular impingement (FAI) is a common determinant of hip pain in young adults and an established risk factor in the subsequent development of osteoarthritis (OA). The mechanism of hip OA secondary to FAI is unknown. Small-animal models are critical translational tools to understand mechanisms of disease and develop interventional therapies. Kamenaga and colleagues proposed a novel animal model to mimic cam-FAI; however, 3D morphology of the induced deformity has not been objectively investigated.
To use statistical shape modeling to quantitatively describe the induced proximal femoral head-neck deformity in order to take the necessary step in validating this animal model as a translational model for human cam-FAI.
Controlled laboratory study.
Six-week-old immature New Zealand White rabbits (n = 13) were subject to right femur physis injury, with left femurs serving as controls. Micro-computed tomography images of femurs were taken at minimum 4 weeks after injury. 3D reconstructions were aligned and underwent statistical shape modeling with 2048 particles placed on each femur. Differences between mean shapes were calculated and analyzed using the Hotelling test. Principal component analysis was used to describe shape variation, and parallel analysis was used to determine the statistically significant modes.
Hotelling test demonstrated significant differences between cam-FAI and control mean shapes ( < .01). The cam-FAI mean shape protruded above the control mean by a maximum of 0.8 mm in the anterolateral head-neck junction with sustained protrusions of ~0.6 to 0.8 mm over the anterosuperior aspect and anteroposterior midline of the femoral head-neck junction. Maximum deviations between individual cam-FAI femurs and the mean control femur ranged between 0.1 and 1.6 mm in the same region. The first 6 modes explained 92.1% of the cumulative variation, and the first 13 modes were statistically significant, confirming the deformity.
The proposed model resulted in a head-neck cam deformity similar to human cam-FAI.
This proposed animal model creates a cam-type deformity similar to that observed in human FAI, helping validate the model as a platform to study mechanisms of hip FAI OA and develop future interventional therapies for this disease.
股骨髋臼撞击症（FAI）是年轻成年人髋关节疼痛的常见决定因素，也是随后发生骨关节炎（OA）的既定风险因素。FAI继发髋OA的机制尚不清楚。小动物模型是理解疾病机制和开发介入治疗的关键转化工具。Kamenaga及其同事提出了一种新型动物模型来模拟凸轮型FAI；然而，诱导畸形的三维形态尚未得到客观研究。
使用统计形状建模来定量描述诱导的近端股骨头-颈畸形，以便在验证该动物模型作为人类凸轮型FAI的转化模型方面迈出必要的一步。
对照实验室研究。
对13只6周龄未成熟的新西兰白兔进行右股骨骨骺损伤，左股骨作为对照。在损伤后至少4周拍摄股骨的微型计算机断层扫描图像。对三维重建进行对齐，并对每根股骨放置2048个粒子进行统计形状建模。使用Hotelling检验计算并分析平均形状之间的差异。主成分分析用于描述形状变化，平行分析用于确定具有统计学意义的模式。
Hotelling检验显示凸轮型FAI与对照平均形状之间存在显著差异（P <.01）。凸轮型FAI平均形状在股骨头-颈前外侧交界处比对照平均形状最多突出0.8 mm，在股骨头-颈交界处的前上方和前后中线持续突出约0.6至0.8 mm。在同一区域，单个凸轮型FAI股骨与平均对照股骨之间的最大偏差在0.1至1.6 mm之间。前6种模式解释了累积变异的92.1%，前13种模式具有统计学意义，证实了畸形。
所提出的模型导致了类似于人类凸轮型FAI的头颈凸轮畸形。
所提出的动物模型产生了类似于人类FAI中观察到的凸轮型畸形，有助于验证该模型作为研究髋FAI OA机制和开发该疾病未来介入治疗的平台。
