Transverse Acetabular Ligament as an Anatomical Landmark for Intraoperative Cup Anteversion in Primary Total Hip Replacement.

OBJECTIVE: To assess the results of the use of transverse acetabular ligament (TAL) as an intraoperative indicator for acetabular cup anteversion alignment during total hip replacement.

STUDY DESIGN: Case series.

PLACE AND DURATION OF STUDY: The Nursing Home Hospital in Baghdad Medical City Complex, Baghdad, Iraq, from October 2014 to June 2015.

METHODOLOGY: Patients were operated through a posterolateral approach for primary total hip arthroplasty (THA) in which transverse acetabular ligament (TAL) was identified and used as indicator for cup anteversion. Those with previous surgery and secondary osteoarthritis due to dysplasia or tumor were excluded. Postoperative anteversion angles were measured by using anteroposterior pelvic radiographs using Pardhan method by two different observers and the perceived quality of operative outcome was directly asked to the patient.

RESULTS: There were a total of 31 patients. The anteversion angle ranged between 5.7 - 24.40°. In addition, the calculated mean angle of 14.7 degrees for the current study sample did not obviously or significantly depart from the required optimum angle of 15 degrees defined by Lewinnek (15 ±10°, p=0.82). For the perceived quality of operative outcome, good outcome (satisfied) was expressed by two-thirds (67.7%) of study subjects after four weeks of surgery.

CONCLUSION: Using transverse acetabular ligament as an intraoperative landmark is a simple, effective, and patientspecific method for proper cup anteversion placement in primary THA.