CT-analysis of the cup position in- or outside the “safe zone” in mechanical guide (MG) vs free-hand (with using transverse acetabular ligament (TAL) by Beverland,
et al.) groups.
The adverse consequences of impingement,
and implant wear have stimulated increasing interest in accurate component orientation in total hip arthroplasty and hip resurfacing .
Hip dislocation is a frequent mode of failure of THA with 0.5% to 10% dislocation rates reported for primary THA and 10% to 25% after revision surgery.
The dislocation risk is multifactorial.
In addition to infection,
issues with the quality of the surrounding soft tissue,
and the type of prosthesis,
the position of the implants plays a major role...
Findings and procedure details
240 THA for femoral neck fracture performed from 2010 to 2013 at a single institution divided in 2 groups: in 140 patients,
alignment made using mechanical guide with goal 45° inclination and 15° anteversion and in 100 patients acetabular component was placed parallel to the TAL (Table1).
Characteristics of the groups
Number of THA
Mean age (yr)
72 (from 63 to 88)
75 (from 61 to 96)
TAL-method is effective for cup placement inside the “safe zone”.
There is a positive correlation between the retroversion and frequency of dislocation in THR.
 Merle C,
Comparison of Native Anatomy with Recommended Safe Component Orientation in Total Hip Arthroplasty for Primary Osteoarthritis.
J Bone Joint Surg Am 2013; 95:e172 (1-7).
 Lazennec JY,
Acetabular Anteversion with CT in Supine,
and Sitting Positions in a THA Patient Population Clin Orthop Relat Res (2011); 469:1103–1109.
 Lewinnek GE,
Dislocation after total hip-replacement arthroplasties.
J Bone Joint Surg Am...