Navigation is Equal to Estimation by Eye and Palpation in Preventing Psoas Impingement in THA

Abstract

Background Iliopsoas tendon impingement is one possible reason for persistent groin pain and diminished functional outcome after THA. So far, estimation by eye and palpation is the standard procedure to intraoperatively assess the distance of the cup to the anterior rim. However, novel technologies such as imageless navigation enable intraoperative measurements of the cup in relation to the psoas tendon and bony landmarks. Questions/purposes We asked whether psoas impingement (1) can be reduced using imageless navigation compared with the standard technique and (2) is associated with specific patient characteristics. Furthermore, we investigated (3) if anterior cup protrusion (overhang) is associated with lower outcome scores for pain and function.Methods The current study is a reanalysis of data from a randomized controlled trial evaluating navigation for THA; 135 patients were randomized for surgery with or without the use of imageless navigation. The risk for anterior protrusion of the cup above the acetabular rim and thus potential psoas impingement, defined as an overhang of the cup above the anterior acetabular rim as measured on postoperative CT, was either controlled with the help of navigation or standard control by eye and palpation intraoperatively. Postoperatively, the anterior protrusion of the cup above the acetabular rim was measured on three-dimensional (3-D) CT by a blinded, external institute. In addition to patient-related outcome measures, the Harris hip score, Hip disability and Osteoarthritis Outcome Score, and EuroQol were obtained 1 year postoperatively. Altogether 123 data sets were available for primary analysis and 115 were available for 1-year followup. Results There was no difference, with the numbers available, between the navigated and the control groups in terms of the mean distance of the cup below the anterosuperior acetabular rim (3.9 mm; À5.3 to 12.6 mm versus 4.4 mm; À7.9 to 13.7 mm; p = 0.72) or the anteroinferior acetabular rim (4.7 mm; À6.2 to 14.8 mm versus 4.2 mm; À7.1 to 16.3 mm; p = 0.29). There was no difference, with the numbers available, in terms of the proportion of cups with anterior overhang (7%, four of 57 versus, 15%, 10 of 66; p = 0.16), respectively. After controlling for potential confounding variables such as cup inclination, cup size, patient age, BMI, stage of arthritis, and length of skin incision, we found cup anteversion (hazard ratio [HR], 0.87; 95% CI, 0.81-0.93; p \ 0.001) and female sex (HR, 3.88; 95% CI, 1.01-14.93; p = 0.049) were associated with a propensity to potential psoas impingement. With the numbers available, there were no differences observed in

Relationship between iliopsoas muscle surface pressure and implant alignment after total hip arthroplasty: a cadaveric study

“…The reported ACPL for symptomatic IPI ranges from 2 to 27 mm in the axial plane on CT scans 7 , 10 , 12 . However, the mean ACPL has been reported to be 0 mm to 17 mm in the axial plane even in patients who are asymptomatic after THA 7 , 10 , 15 , 16 . Thus, the overlap of ACPL between symptomatic and asymptomatic IPI is wide, ranging from 2 to 17 mm.…”

“…Thus, the overlap of ACPL between symptomatic and asymptomatic IPI is wide, ranging from 2 to 17 mm. Despite general agreement that large ACPL causes symptomatic IPI, the association between small ACPL and symptomatic IPI remains unclear 7 , 10 , 12 , 15 , 16 . We consider the minimum ACPL value associated with symptoms to be the most clinically relevant.…”

Which Safe Zone Is Safe in Total Hip Arthroplasty? The Effect of Bony Impingement

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Recent Trends, Technical Concepts and Components of Computer-Assisted Orthopedic Surgery Systems: A Comprehensive Review

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