Validation of use of transverse acetabular ligament and mechanical angle guide device to orient the acetabular cup

Abstract

Aim: To verify if transverse acetabular ligament (TAL) can be used as an anatomical landmark to reliably orient the cup in primary total hip arthroplasty and compare it to acetabular cups placed with the help of mechanical angle guide (MAG) device. Materials and methods: Thirty Five patients with primary total hip arthroplasty, all performed by the same surgeon were included in the study. All patients had undergone surgery by anterolateral approach and all were cementless total hip arthroplasty. TAL was used as a reference guide for positioning of the cup in one group while MAG device was used in the other. Post operatively CT was done to confirm the version and inclination of the acetabular cup and the femoral stem version. SPSS was used for statistical analysis. Results: 18 males and 17 females were included. The most common etiological cause for THR was secondary osteoarthritis due to AVN (40%). At 18 months follow up, there was just 1 case of dislocation in group in which angle guide device was used. The mean anteversion of the acetabular cup on CT findings was 23.82 by using TAL while 18.35 with help of MAG device (P < 0.05). All were within Leweniks safe zone. Conclusions: The TAL and MAG device both can be effectively used to align the acetabulum component. TAL is patient specific intraoperative landmark which is not affected by patient positioning while angle guide device can give false positive assessment of cup version.

Application of transverse acetabular ligament in total hip arthroplasty: a systematic review

“…There were 3 level II studies [ 17 , 24 , 33 ], 6 level III studies (retrospective cohorts) [ 22 , 23 , 26 , 27 , 29 ]– 30 ], 1 level I RCT [ 20 ], and 9 level IV studies [ 9 , 12 –[ 13 , 21 , 25 , 28 , 31 ]– 32 , 34 ]. Of the level II papers are prospective study, one compared the anatomical anteversion of TAL and the TAL-guided acetabular component orientation in relation to disease and gender using 3D reconstruction of computed tomography(CT) images [ 24 ], one was a single comparison of the TAL vs. free-hand technique for acetabular component orientation [ 17 ], and the final study compared the TAL to mechanical angle guide device placing acetabular component [ 33 ]. The only level I RCT that compared freehand introduction of acetabular component with TAL-guided introduction for anteversion of acetabular component [ 20 ].…”

“…Three of the 19 (15.8%) studies were controlled trial of two groups [ 17 , 20 , 33 ]. Two studies [ 17 , 20 ] compared freehand introduction of acetabular component with TAL-guided introduction for anteversion of acetabular component.…”

“…In conclusion, both TAL and mechanical angle guide device can effectively locate acetabular component. The TAL is patient-specific intraoperative landmark independent of patient position, while the mechanical angle guide device can lead to false assessments of acetabular component orientation [ 33 ].…”

“…Eleven of the 19 (57.9%) studies reported rate of dislocations by using the TAL as a landmark for the orientation of the acetabular component [ 12 , 13 , 17 , 20 – 22 , 28 – 30 , 33 ]– 34 ]. there was a total of 2,355 patients and 2,386 hips included, the average rate of dislocations was 0.75%, the follow-up time ranged from 1 to 96 months.…”

“…there was a total of 2,355 patients and 2,386 hips included, the average rate of dislocations was 0.75%, the follow-up time ranged from 1 to 96 months. There are three comparative studies involving dislocation rates [ 17 , 20 , 33 ]. In total, 90 patients and 90 hips were included in the TAL group.…”