Evaluation of Pre-Operative Hip Range of Motion under General Anaesthesia

Hip range of motion (ROM) may be an important pre-operative variable, however, measurement of hip ROM can be affected by various factors. The purposes of this study were to compare conventional pre-operative ROM measurements with those measurements obtained under general anaesthesia, and to better define the associations between pre-operative hip ROM, and demographic, functional, and diagnostic variables.

Conventional pre-operative hip ROM and ROM under general anaesthesia were prospectively measured in 471 hips. Harris pain score, the Crowe classification, and the diagnosis were also investigated. The hip ROM in all directions under general anaesthesia was significantly greater than conventional pre-operative hip ROM. There were correlations between conventional pre-operative hip ROM and the Harris hip pain score. Hip ROM with Crowe type I deformity under anaesthesia was significantly greater than in hips with type II, III or IV. ROM under anaesthesia of osteonecrosis hips was significantly greater than osteoarthritis and dislocated hips. Conventional pre-operative ROM in men was greater in flexion and external rotation compared to women. Internal rotation motion in women in both conventional pre-operative ROM and ROM under anaesthesia was greater than in men.

Hip pain, Crowe classification and diagnosis could influence pre-operative hip ROM. Measurement of hip ROM under general anaesthesia could better reflect true ROM compared to measurement without anaesthesia.