Exposing the transverse acetabular ligament in the presence of large floor osteophytes in primary total hip arthroplasty

Background/objective: The transverse acetabular ligament (TAL) can be used to position the acetabular cup and may help to improve the accuracy of primary total hip arthroplasty (THA). However, because the TAL may be covered by osteophytes, the ability to find the TAL varies greatly in the reported literature. In the present study, we introduce 2 methods and make a comparison between them to identify the easier procedure for finding an osteophyte-covered TAL. Methods: During primary THA operations conducted from January 2012 to June 2015, a total of 100 patients (100 hips) were confirmed to have an osteophyte-covered TAL following the exposure of the acetabulum and removal of all soft tissues covering the TAL. These 100 patients were enrolled in this study. 2 methods were used to identify the TAL: the use of a bone chisel or a small reamer, and patients were allocated randomly to 1 of these 2 methods. The proportion of patients in whom TAL was identified was compared between the 2 methods using the chi-square test. Results: The percentage of patients in whom the TAL was found using a bone chisel was 54.1% (26/48), whereas the percentage was 94.2% (49/52) in patients for whom a small reamer was used. The difference between the 2 methods was statistically significant (chi-square test, p<0.05). Conclusions: The TAL can be found more easily with a small reamer than with a bone chisel.