Femoral head-neck ratio in patients with Cam-type femoroacetabular impingement and healthy adults and its impact on surgical strategy

Abstract

Objective To explore the difference of the femoral head-neck ratio (FHNR) in patients with Cam-type femoroacetabular impingement (FAI) and healthy adults and its impact on surgical strategy.Methods We measured the FHNR using method described by Doherty.468 healthy adults without hip symptoms acted as controls in the study,including 313 males and 155 females,with the mean age of 42.4years (range,17-82 years).There were 17 patients (24 hips) in the Cam-type FAI group.The maximum diameter of the femoral head and the minimum vertical diameter of femoral neck on both sides were measured by Digimizer software on the standard anteroposterior pelvis film.The ratio of femoral head to femoral neck was calculated and was compared.The surgery was performed in 7 cases (8 hips) with FAI.The Harris score and internal rotation angle was also compared.Results The FHNR of control group and Cam-type FAI group was 1.48±0.09(1.33-1.69) and 1.30±0.13 (1.01-1.46) separately (P＜0.01).The volume of osteophyte removed during operation was related with the FHNR.The average Harris score had improved from 63.4±8.2(52-76) preoperatively to 89.2±3.5(84-95) postoperatively.The average internal rotation angle had improved from 2.5°±2.7°(0°-5°) preoperatively to 12.5±3.8°(5°-15°) postoperatively.Conclusion FHNR measurement is useful for the diagnosis and surgical treatment of Cam-type FAI. Key words: Adult; Femur; ,Anthropometry; Hip; Surgical procedures,operative