Surface Attachment Points for Lateral Extra‐articular Procedures Are in Close Proximity to the Femoral and Tibial Physes in Skeletally Immature Patients

Purpose To quantitatively determine the attachment location for lateral extra‐articular procedures (LEAP) relative to the lateral physes using magnetic resonance imaging (MRI) to guide implant placement and physeal avoidance. Methods This study included a consecutive series of skeletally immature patients who underwent a knee MRI between 2000 and 2023. The LEAP attachment locations relative to the femoral and tibial physes were determined using MRI in skeletally immature knees without evidence of knee injury. Results Five hundred ninety‐nine individual knee MRI studies met the inclusion criteria (285 males, 314 females). Chronological and bone age for both males ( r  = .92, P  = .0001) and females ( r  = .89, P  = .0001) were strongly correlated; mean chronologic age was 14.4 years (SD 2.8) for males and 14.1 years (SD 2.6) for females. Mean distance from femoral LEAP attachment to the physis was 8.7 mm (SD .1) in males and 7.1 mm (SD .1) in females, increased with increasing age for males ( P  = .0001). Mean distance from the tibial ALL attachment to the physis was 11.0 mm (SD .1) in males and 9.4 mm (SD .1) in females, increased with increasing age ( P  = .0001). Mean lateral‐femoral physeal obliquity was 28.5° (SD .4) in males and 30.0° (SD .4) in females ( P  = .0001). Mean tibial physeal obliquity 29.2° (SD .4) in males and 33.1° (SD .4) in females ( P  = .0004). The proximity of femoral surface attachment was closer to the physis than the tibial attachment across all patients, 7.8 mm vs 10.1 mm ( P  = .0001). Conclusions The lateral femoral and tibial physes are close to surface attachment points for LEAP performed in conjunction with anterior cruciate ligament reconstruction in skeletally immature patients. The femoral LEAP surface attachment was significantly closer to the physis compared to the tibial attachment. Clinical Relevance LEAP are performed more frequently with anterior cruciate ligament reconstruction in skeletally immature patients and avoidance of physeal injury is important.