Limited hip flexion and internal rotation resulting from early hip impingement conflict on anterior metaphysis of Patients with untreated Severe SCFE using 3D modelling
- 2022-11-01.
/pmc/articles/PMC7614193/ /pubmed/36099440
INTRODUCTION: SCFE is the most common hip disorder in adolescent patients that can result in complex 3D-deformity and hip preservation surgery (e.g. in-situ-pinning or proximal femoral osteotomy) is often performed. But there is little information about location of impingement. Purpose/Questions The purpose of this study was to evaluate(1) impingement-free hip flexion and internal rotation(IR), (2)frequency of impingement in early flexion(30°-60°) and (3)location of acetabular and femoral impingement in IR in 90° of flexion(IRF-90°) and in maximal flexion for patients with untreated severe SCFE using preoperative 3D-CT for impingement-simulation. PATIENTS AND METHODS: A retrospective study involving 3D-CT scans of 18 patients(21 hips) with untreated severe SCFE(slip-angle>60°) was performed. Preoperative CT scans were used for bone segmentation of preoperative patient-specific 3D-models. Three patients(15%) had bilateral SCFE. Mean age was 13±2(10-16) years and 67% were male patients (86% unstable slip, 81% chronic slip). The contralateral hips of 15 patients with unilateral SCFE were evaluated(control group). Validated software was used for 3D impingement-simulation (equidistant-method). RESULTS: (1)Impingement-free flexion(46±32°) and IRF-90°(-17±18°) were significantly(p<0.001) decreased in untreated severe SCFE patients compared to contralateral side(122±9° and 36±11°). (2)Frequency of impingement was significantly(p<0.001) higher in 30° and 60° flexion (48% and 71%) of patients with severe SCFE compared to control group(0%). (3)Acetabular impingement conflict was located anterior-superior(SCFE patients), mostly 12 o'clock (50%) in IRF-90° (70% on 2 o'clock for maximal flexion). Femoral impingement was located on anterior-superior to anterior-inferior femoral metaphysis(between 2-6 o'clock, 40% on 3 o'clock and 40% on 5 o'clock) in IRF-90° and on anterior metaphysis(40% on 3 o'clock) in maximal flexion and frequency was significantly(p<0.001) different compared to control group. CONCLUSION: Severe SCFE patients have limited hip flexion and IR due to early hip impingement using patient-specific preoperative 3D-models. Due to the large variety of hip motion, individual evaluation is recommended to plan the osseous correction for severe SCFE patients.