Mater Children's Hospital, Brisbane, Queensland, Australia. ; School of Medicine, University of Queensland, Brisbane, Queensland, Australia.
Orthop J Sports Med. 2013 Sep 5;1(4):2325967113502638. doi: 10.1177/2325967113502638. eCollection 2013 Sep.
Medial patellofemoral ligament (MPFL) reconstruction in adults often utilizes screw fixation in the distal femur. The aim was to define the safety of similar fixation in young patients, with respect to their open physis.
To define the age-related relationship between the femoral insertion of the MPFL and the medial aspect of the distal femoral physis on magnetic resonance imaging (MRI) scans. The study investigates whether screw fixation at this point is safe with respect to patient age and screw inclination.
Cross-sectional study.
Retrospective review of the MRI scans of 159 skeletally immature patients. The femoral insertion of the MPFL was defined with respect to the distal femoral physis. The predicted paths of 2-cm screw fixation were simulated both parallel to the joint line and 45° distally oblique; physeal and joint penetration were noted when present. Results are plotted against age and compared as quartile ranges.
The femoral insertion of the MPFL was found to be distal to the distal femoral physis in all patients by an average of 10 mm (range, 2-16 mm). The mean distance increases slightly with age in a nonlinear relationship (r = 0.51, P < .001) from 9 mm at age 10 years to 12 mm by age 16 years. For the classic, parallel screw, the risk of physeal breach is high for all age groups (mean, 64%). For the novel, oblique screw, joint penetration and physeal breach were less prevalent (mean, 13%), and importantly, the vast majority of these breaches were in younger children (age <9 years 9 months). With oblique screws, older children were at significantly lower risk than younger children (<3% vs 48%; P < .001).
This study accurately defines the relationship between the femoral insertion of the MPFL and the distal femoral physis in children and adolescents. A high risk of potentially poor outcomes was found during anatomic reconstruction of the MPFL in children utilizing classic (parallel) screw fixation, irrespective of age. However, in children older than 10 years, a 20-mm screw, from the anatomic MPFL insertion and directed 45° distally oblique, should be safe in 98% of patients.
成人内侧髌股韧带（MPFL）重建术常采用股骨远端螺钉固定。本研究旨在确定该方法在年轻患者中应用的安全性，特别是针对其骺板未闭的情况。
在磁共振成像（MRI）上确定 MPFL 在股骨上的止点与股骨远端骺板内侧之间的年龄相关性。本研究旨在探讨该部位螺钉固定的安全性是否与患者年龄和螺钉倾斜角度有关。
横断面研究。
回顾性分析 159 例骨骼未成熟患者的 MRI 扫描结果。根据股骨远端骺板确定 MPFL 的股骨止点。模拟 2cm 螺钉固定的预测路径，分别与关节线平行和 45°向远端斜行；记录当存在骺板和关节穿透时的穿透情况。结果根据年龄进行绘制，并按四分位范围进行比较。
所有患者的 MPFL 股骨止点均位于股骨远端骺板远端，平均距离为 10mm（范围，2-16mm）。平均距离随年龄呈非线性增加（r=0.51，P<.001），从 10 岁时的 9mm 增加到 16 岁时的 12mm。对于经典的平行螺钉，所有年龄段的骺板穿透风险都很高（平均为 64%）。对于新型的斜行螺钉，关节穿透和骺板穿透的发生率较低（平均为 13%），重要的是，这些穿透绝大多数发生在年幼的儿童（<9 岁 9 个月）。使用斜行螺钉时，年龄较大的儿童发生穿透的风险显著低于年龄较小的儿童（<3% vs 48%；P<.001）。
本研究准确地定义了儿童和青少年 MPFL 在股骨上的止点与股骨远端骺板之间的关系。在儿童中进行 MPFL 的解剖重建时，采用经典（平行）螺钉固定时，无论年龄大小，都存在潜在不良结果的高风险。然而，在 10 岁以上的儿童中，从解剖 MPFL 插入点以 45°向远端斜行方向使用 20mm 螺钉应可安全应用于 98%的患者。
