A cadaveric study of posterior dislocation after total hip replacement-effects of head diameter and acetabular anteversion.
The size of the femoral head and acetabular anteversion are crucial for stability in total hip replacements. This study examined the effects of head diameter and acetabular anteversion on the posterior instability after total hip replacement in an in vivo setting. The acetabular shell was inserted at 0-20° of anteversion at five degree intervals. By using different head sizes (28 mm, 32 mm, 36 mm), the degrees of dislocation were recorded by computer navigation. The 36-mm group consistently showed better stability compared with the 32- and 28-mm groups, regardless of the degree of cup anteversion. Within each group of head size, the hip was significantly more stable when the cup anteversion increased from 0° to 10°. The difference became insignificant when it increased from 15° to 20°.
Ng
Fu Yuen
FY
Orthopaedics and Traumatology, Queen Mary Hospital, Hong Kong, China. charlesnfy@netvigator.com
Zhang
Jiang Tao
JT
Chiu
Kwong Yuen
KY
Yan
Chun Hoi
CH
D000077:Acetabulum / Q000033:anatomy & histology*; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D005270:Femur Head / Q000033:anatomy & histology*; D006621:Hip Joint / Q000033:anatomy & histology* / Q000502:physiology; D006622:Hip Prosthesis; D006801:Humans; D004204:Joint Dislocations; D007593:Joint Instability / Q000209:etiology / Q000517:prevention & control; D008297:Male; D011183:Postoperative Complications; D011474:Prosthesis Design; D016059:Range of Motion, Articular / Q000502:physiology