Department of Rehabilitation Medicine, National Institutes of Health, Bethesda, Maryland, USA.
The Orthopaedic Center, a Division of CAO, Rockville, Maryland, USA.
Am J Sports Med. 2024 Apr;52(5):1282-1291. doi: 10.1177/03635465241233732.
Research on the cause of lateral patellar dislocation (LPD) has focused on trochlear morphologic parameters, joint alignment, and patellofemoral soft tissue forces. A paucity of information is available regarding how patellar morphologic parameters influence the risk for LPD.
PURPOSE/HYPOTHESIS: The purpose was to assess whether patellar morphology is a risk factor for recurrent LPD. It was hypothesized that (1) patients with recurrent LPD would have decreased patellar width and volume and (2) patellar morphologic parameters would accurately discriminate patients with recurrent LPD from controls.
Cohort study (diagnosis); Level of evidence, 3.
A total of 21 adults with recurrent LPD (age, 29.7 ± 11.1 years; height, 170.8 ± 9.9 cm; weight, 76.1 ± 17.5 kg; 57% female) were compared with 21 sex- and height-matched controls (age, 27.2 ± 6.7 years; height, 172.0 ± 10.6 cm; weight, 71.1 ± 12.8 kg; 57% female). Three-dimensional axial fat-saturated magnetic resonance imaging scans were used to measure patellar medial, lateral, and total width; patellar volume; patellar medial and lateral facet length; the Wiberg index; and previously validated knee joint alignment and femoral shape measurements (eg, tibial tuberosity to trochlear groove distance, trochlear dysplasia).
The LPD group demonstrated reduced medial patellar width (Δ = -3.6 mm; < .001) and medial facet length (Δ = -3.7 mm; < .001) but no change in lateral width or facet length. This resulted in decreased total patellar width (Δ = -3.2 mm; = .009), decreased patellar volume (Δ = -0.3 cm; = .025), and an increased Wiberg index (Δ = 0.05; < .001). No significant differences were found for all other patellar shape measures between cohorts. Medial patellar width was the strongest single discriminator (83.3% accuracy) for recurrent LPD. Combining medial patellar width, patellofemoral tilt, and trochlear groove length increased the discrimination to 92.9%.
The medial patellar width was significantly smaller in patients with recurrent LPD and was the single most accurate discriminator for recurrent LPD, even compared with traditional trochlear shape and joint alignment measures (eg, trochlear dysplasia, patella alta). Therefore, medial patellar morphology should be assessed in patients with LPD as a risk factor for recurrence and a potential means to improve treatment.
对外侧髌脱位（LPD）病因的研究集中在滑车形态参数、关节对线和髌股软组织力量上。关于髌股形态参数如何影响 LPD 的风险，相关信息较少。
目的/假设：目的是评估髌股形态是否是复发性 LPD 的危险因素。假设（1）复发性 LPD 患者的髌股宽度和体积会减小；（2）髌股形态参数能够准确区分复发性 LPD 患者和对照组。
队列研究（诊断）；证据水平，3 级。
共纳入 21 例复发性 LPD 患者（年龄 29.7 ± 11.1 岁；身高 170.8 ± 9.9 cm；体重 76.1 ± 17.5 kg；57%为女性），并与 21 例性别和身高匹配的对照组（年龄 27.2 ± 6.7 岁；身高 172.0 ± 10.6 cm；体重 71.1 ± 12.8 kg；57%为女性）进行比较。采用三维轴向脂肪饱和磁共振成像扫描测量髌股内侧、外侧和总宽度；髌股体积；髌股内侧和外侧关节面长度；Wiberg 指数；以及先前验证的膝关节对线和股骨形态测量值（例如，胫骨结节至滑车沟距离、滑车发育不良）。
LPD 组的髌股内侧宽度（Δ=-3.6mm； <.001）和内侧关节面长度（Δ=-3.7mm； <.001）减小，但外侧宽度或关节面长度无变化。这导致总髌股宽度（Δ=-3.2mm； =.009）、髌股体积（Δ=-0.3cm； =.025）减小，Wiberg 指数（Δ=0.05； <.001）增加。两组间其他髌股形态测量值无显著差异。髌股内侧宽度是复发性 LPD 的最强单项鉴别指标（准确率 83.3%）。将髌股内侧宽度、髌股倾斜角和滑车沟长度结合起来，可将鉴别准确率提高到 92.9%。
复发性 LPD 患者的髌股内侧宽度明显较小，即使与传统的滑车形态和关节对线测量值（例如，滑车发育不良、高位髌骨）相比，髌股内侧宽度也是复发性 LPD 的最准确鉴别指标。因此，LPD 患者应评估髌股内侧形态，作为复发的危险因素，并可能作为改善治疗的手段。
