Femoral impingement in maximal hip flexion is anterior-inferior distal to the cam deformity in femoroacetabular impingement patients with femoral retroversion: implications for hip arthroscopy

Bone & Joint Research

article

Adam Boschung¹  Senta Faulhaber¹  Ata Kiapour²  Young-jo Kim²  Eduardo N. Novais²  Simon D. Steppacher³  Moritz Tannast⁴  Till D. Lerch¹ 

[1] Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Inselspital, Bern University Hospital;Department of Pediatric Orthopedic Surgery, Boston Children's Hospital, Harvard Medical School;Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern;Department of Orthopaedic Surgery and Traumatology, Fribourg Cantonal Hospital, University of Fribourg

关键词: FAI;    Femoroacetabular impingement;    Extra-articular hip impingement;    Subspine impingement;    Hip arthroscopy;    Hip preservation surgery;    femoral retroversion;    cam deformities;    femoroacetabular impingement;    hip flexion;    hips;    flexion;    cam-type femoroacetabular impingement;    CT scans;    hip pain;    hip arthroscopy;   

DOI  :  10.1302/2046-3758.121.BJR-2022-0263.R1

学科分类：骨科学

来源: British Editorial Society Of Bone And Joint Surgery

【 摘 要 】

AimsFemoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients.MethodsA retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method).ResultsMean impingement-free flexion of patients with mixed-type FAI (110° (SD 8°)) and patients with pincer-type FAI (112° (SD 8°)) was significantly (p < 0.001) lower compared to the control group (125° (SD 13°)). The frequency of extra-articular subspine impingement was significantly (p < 0.001) increased in patients with pincer-type FAI (57%) compared to cam-type FAI (22%) in 125° flexion. Bony impingement in maximal flexion was located anterior-inferior at femoral four and five o’clock position in patients with cam-type FAI (63% (10 of 16 hips) and 37% (6 of 10 hips)), and did not involve the cam deformity. The cam deformity did not cause impingement in maximal flexion.ConclusionFemoral impingement in maximal flexion was located anterior-inferior distal to the cam deformity. This differs to previous studies, a finding which could be important for FAI patients in order to avoid exacerbation of hip pain in deep flexion (e.g. during squats) and for hip arthroscopy (hip-preservation surgery) for planning of bone resection. Hip impingement in flexion has implications for daily activities (e.g. putting on shoes), sports, and sex.

【 授权许可】

CC BY-NC