Clinical trial NCT04623073: EO Footprint as a Landmark During DAA THA
Official title: The External Obturator Footprint as a Landmark for Stem Dept - Clinical Validation
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Coxarthrosis
Keywords: Total hip Arthroplasty
leg length
templating
direct anterior approach
external obturator footprint
Lead sponsor: Universitaire Ziekenhuizen KU Leuven
Sponsor class: OTHER
First posted: 2020-11-10
Enrollment: 135
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: All patient who underwent THA via DAA by a single surgeon who routinely documents the distance from the shoulder of the stem to the upper border of the EO tendon

Brief summary: One of the goals of Total Hip Arthroplasty (THA) is to reconstruct leg length as adequately as possible. In order to achieve this one needs landmarks that are visible both on the templating X ray as well as during surgery. The classical posterior and lateral approaches often rely on the distance from the greater trochanter (GT) to the shoulder of the femoral stem or the distance from the lesser trochanter (LT) to the side of the neck osteotomy. If the surgeon finds out on the digital template that the distance from the GT to the shoulder of the implant should be X mm to achieve equal leg length, than the surgeon can try to reconstruct this during surgery. During the Direct Anterior Approach (DAA) these landmarks usually are not visible or require additional dissection injuring important soft tissue structures along the way. One anatomical structure that appears to be always visible during the DAA is the External Obturator tendon (EO). It was recently confirmed that the level of insertion of the EO onto the proximal femur can also always be determined on pre-operative X rays. It therefore represents one of the few landmarks that is visible both on the templating X ray as well as during DAA THA. Indeed, many hip surgeons, including ourselves, believe that if the shoulder of the femoral stem is near the insertion of the EO leg length cannot be far off. However, there is no clinical data to support this. The investigators would therefore like to the correlate the distance observed intra-operatively to the actual established distance on the post-operative X ray.


Eligibility criteria: Inclusion Criteria:

* All patient who underwent THA via DAA by a single surgeon who routinely documents the distance from the shoulder of the stem to the upper border of the EO tendon

Exclusion Criteria:

* Distance not noted
* No radiographs available

Primary outcomes:
measure: Correlation between the distance measured intra-operatively and presumed distance on the pelvic radiographs
timeFrame: 2 days
Secondary outcomes:
measure: Visibility of the EO tendon intra-operatively
timeFrame: 2 days
measure: Inter and intra-rater reliability
timeFrame: 2 days
Other outcomes:
Locations:
city: Leuven
country: Belgium
facility: University Hospitals Leuven - Gasthuisberg
Study officials:
References:
citation: Rudiger HA, Fritz B, Impellizzeri FM, Leunig M, Pfirrmann CW, Sutter R. The external obturator footprint as a landmark in total hip arthroplasty through a direct anterior approach: a CT-based analysis. Hip Int. 2019 Jan;29(1):96-101. doi: 10.1177/1120700018761320. Epub 2018 May 21.
citation: Vles G, Meynen A, De Mulder J, Ghijselings S. The External Obturator Footprint Is a Usable, Accurate, and Reliable Landmark for Stem Depth in Direct Anterior THA. Clin Orthop Relat Res. 2021 Aug 1;479(8):1842-1848. doi: 10.1097/CORR.0000000000001799.