Effects of the femoral offset and the head size on the safe range of motion in total hip arthroplasty.
The purpose of this study was to quantify the effects of femoral offset and head size on range of motion (ROM) after total hip arthroplasty. Modular prostheses were implanted into 11 cadaveric hips using a posterolateral approach and tested for ROM with 3 different offsets and 5 different femoral head sizes. Increasing the femoral offset to 4 and 8 mm resulted in 21.1 degrees and 26.7 degrees of improved flexion, and 13.7 degrees and 21.2 degrees of improved internal rotation, respectively. The ROM improved in a head size-dependent manner primarily because of increasing the jumping distance of the femoral head rather than delaying any impingement. In contrast, the effectiveness of femoral offset was driven by delayed osseous impingement.
Department of Orthopedic Surgery, Graduate School of Medical, Sciences, Kyushu University, Fukuoka, Japan.
Akinobu
A
Matsushita
Yasuharu
Y
Nakashima
Seiya
S
Jingushi
Takuaki
T
Yamamoto
Akio
A
Kuraoka
Yukihide
Y
Iwamoto
D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods*; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000150:complications / Q000209:etiology; D005269:Femur / Q000601:surgery; D006621:Hip Joint / Q000502:physiology*; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D016059:Range of Motion, Articular