Reliability and validity of the functional combined anteversion measurement method using standing lateral radiography after total hip arthroplasty

Abstract

Background: The functional safe zone of combined anteversion (CA) shows a superior predictive value for dislocation after total hip arthroplasty (THA) compared to that of the Lewinnek safe zone. Thus, it is necessary to establish a feasible and accurate method for assessing CA for the evaluation of dislocation risk.We aimed to evaluate the reliability and validity of using standing lateral (SL) radiographs for determining CA.Methods: Sixty-seven patients who underwent SL radiography and computed tomography (CT) scans after THA were included. Radiographic CA values were obtained via the calculation of the sum of the acetabular cup and femoral stem anteversion (FSA) measurements as obtained from the SL radiographs. Acetabular cup anteversion (AA) was measured based on the tangential line to the face of the cup, whereas FSA was calculated using the developed formula based on the neck-shaft angle. The intra-observer and inter-observer reliabilities for each measurement were examined. Radiological CA values were compared with the CT scan measurements to evaluate their validity. Results:The intra-observer and inter-observer agreements of the SL radiography were excellent [intraclass correlation coefficient (ICC) ≥0.90]. The radiographic measurements correlated well with the CT scan measurements (r=0.869, P<0.001). The mean difference between the radiographic and CT scan measurements was −0.55°±4.68° and ranged from 0.3° to 2.2° in terms of the 95% confidence interval (CI).Conclusions: SL radiography is a reliable and valid imaging tool for the assessment of functional CA.

Challenges in Total Hip Arthroplasty with Prior Spinal Arthrodesis: A Comprehensive Review of Biomechanics, Complications, and Surgical Strategies

“…The transverse acetabular ligament is a reference during surgery to guide the cup implantation within Lewinnek’s plane. However, in the presence of altered PT, relying solely on the transverse acetabular ligament becomes less reliable, as each degree of posterior PT corresponds to 0.7° of cup anteversion, resulting in inaccurate cup placement [ 25 , 26 ]. Because there is a loss of physiological pelvic adaptation mechanisms in the patient undergoing LA in standing and sitting positions, cup, and stem positioning might be even more crucial [ 27 , 28 ] and might be customized to specific patient anatomy and biomechanics to prevent complications.…”

“…The complex interplay between spinal and hip biomechanics and the demonstrated superior incidence of THA dislocation in patients with prior LA necessitates detailed preoperative planning and a personalized, patient-specific approach [ 25 , 26 , 27 , 28 ]. Recent literature on surgical strategies fails to demonstrate any difference between the anterior and posterior approaches in terms of change in postoperative PT, as shown by Inoue et al [ 18 ].…”

Superior outcomes of total hip arthroplasty without prior lumbar arthrodesis: a systematic review and meta-analysis

“…The transverse acetabular ligament has been used as a reference during surgery to guide cup implantation within the safe zone described by Lawinnek et al [ 50 ]. However, when there is an altered pelvic tilt, relying solely on the transverse acetabular ligament becomes less reliable, as each degree of posterior pelvic tilt corresponds to 0.7° of cup anteversion, leading to inaccurate cup positioning [ 52 , 53 ].…”